When Spock begins to exhibit strange, erratic behavior, Kirk asks McCoy to conduct a medical examination. McCoy concludes that Spock is experiencing a potentially lethal internal distress.Review
Spock explains to them that Vulcans are married as children with the understanding that they will fulfill this commitment when they become adults. Spock has reached this time, the "pon farr," and if he doesn't get to Vulcan immediately to mate with his bride, T'Pring, he will die. Kirk jeopardizes his career by disobeying a direct order to the contrary from Starfleet, and proceeds with all possible speed to Vulcan. As Spock's friends, Kirk and McCoy are invited to witness the marriage ritual - the "Koon-ut-kal-if-fee." T'Pau, a highly respected member of the high-counsel, will conduct the ceremony.
Trouble starts when T'Pring announces she would rather marry Stonn, a full Vulcan. T'Pring evokes her right to have Spock fight for her. However, she chooses Kirk as her champion. Fearing his friend is too weak to fight, Kirk agrees. It is only then he is informed that it is to be a fight to the death.
The fight ensues and Spock quickly demonstrates physical superiority. McCoy objects to T'Pau that Kirk isn't used to the Vulcan atmosphere and climate. He asks to inject the captain with a tri-ox compound to compensate. T'Pau agrees and Kirk is given the injection.
During the fight, Spock kills Kirk and McCoy accompanies the captain's body back to the U.S.S. Enterprise. Spock, his mating urges curbed by the knowledge that Kirk, his friend and captain, is dead by his own hand, relinquishes T'Pring to Stonn. He solemnly returns to the starship. There he finds Kirk alive and well, having been injected not with tri-ox, but with a knock-out drug which simulated the signs of death. Overjoyed, Spock smiles and utters a delighted "Jim!" before returning to his controlled, logical self.
As the U.S.S. Enterprise nears the planet Pollux IV, a huge, green hand made of energy materializes in space, catching the U.S.S. Enterprise and holding it captive. Kirk and a landing party are transported to the planet's surface where they find a being who claims to be Apollo, the last of the Greek gods who dwelled on ancient Earth's Mount Olympus. All the other gods, Apollo tells Kirk, died of loneliness when they left their home of Mount Olympus. Apollo's plan for the U.S.S. Enterprise crew is that they settle on Pollux IV and worship their god, Apollo.Review
Sensors show that Apollo's god-like abilities come from an organic ability to use energy from sources outside himself. His apparent powers include storms, thunderbolts and an ability to grow into a giant, towering above the Enterprise landing party.
Attempts to foil Apollo's plans are hampered by Lieutenant Carolyn Palamas, who has fallen in love with the god and whom Apollo decides will be his bride. Scotty, who has beamed down with the party, had harbored hopes of romance with the young lieutenant and objects to Apollo's attentions. Apollo's response is to hurtle the engineer through the air by way of a thunderbolt.
Spock determines that the god's powers come from his temple. When Kirk tells Lt. Palamas to reject Apollo, which she reluctantly does, the captain uses the U.S.S. Enterprise's weapons to destroy Apollo's temple. Apollo, rejected by a mortal woman and bereft of his powers, spreads himself upon the winds to join his fellow gods.
The U.S.S. Enterprise is sent to investigate the destruction of the Malurian system and its four billion inhabitants. When it arrives at the coordinates, the starship itself is threatened by a space going, self-contained computer/probe calling itself Nomad. When Kirk identifies himself by name, Nomad mistakes him for "The Kirk," and thinks him to be his creator.Review
Nomad is beamed aboard the U.S.S. Enterprise and promptly erases Uhura's memory and kills Scotty, claiming that neither life form was perfect. At Kirk's demand Nomad repairs "the unit Scott," bringing him back to life.
Spock attempts a Vulcan mind meld with Nomad and learns that it was created on Earth in the twenty-first century by scientist Jackson Roykirk. Nomad's program was to seek out new life and report back to Earth. Damaged in space by a meteor, Nomad drifted until it found Tan Ru, an alien probe designed to sterilize soil. Using their self-repair systems, the two probes combined themselves into one. Nomad's programming was damaged and by joining with Tan Ru's now believes its mission is to seek out life and destroy anything that it does not believe perfect.
Kirk convinces Nomad that it had mistaken him, Captain James T. Kirk, for Nomad's creator, Jackson Roykirk, thus making Nomad imperfect and a candidate for "sterilization." A confused Nomad begins to self-destruct, exploding just after Kirk beams the changeling into space. Kirk checks on Uhura's progress after the attack by Nomad. McCoy informs him that her brain is undamaged and she must simply "relearn" what the probe erased.
Caught in the beginnings of an ion storm, Kirk, McCoy and Uhura interrupt their negotiations with the Halkans for dilithium crystals, to return to the U.S.S. Enterprise. Scotty beams the landing party aboard as a burst from the storm hits the starship. The transporter malfunctions, sending Kirk, McCoy, Scotty and Uhura into an alternate universe. In this world, they soon discover the "Galactic Empire" is maintained by fear and assassination. Now, aboard the Imperial Starship Enterprise, the four must find a way to remain undetected until they can return to their own universe.Review
Meanwhile, the parallel versions of Kirk, Scott, McCoy and Uhura have been beamed on board the positive U.S.S. Enterprise. Their behavior is so different from their counterparts that Spock immediately realizes something is wrong. He had the four imprisoned until the transporter could be checked and repaired.
On the I.S.S. Enterprise, the parallel Chekov is foiled in an attempt to assassinate Kirk. When Kirk refuses to give an order to destroy the Halkans, who have refused to give up their dilithium crystals, the parallel Spock becomes suspicious.
The Imperial Fleet sends a secret message to the parallel Spock, telling him to kill Captain Kirk and assume command of the starship. Finding an unexpected ally in the parallel Spock, Kirk continues to stall while his three comrades gather the information needed to send them back to their own universe.
Parallel Spock has no desire to become captain, and therefore a mark for assassination. Along with Lieutenant Marlena Moreau, who wants the parallel Kirk back because she is "the Captain's woman," they help return the four U.S.S. Enterprise officers to their own world. Before he goes, Kirk talks to the bearded Spock, telling him the advantages of a Federation-like system over the anarchy of this universe. Spock seems almost convinced that he should in fact get rid of his Kirk, seize control of the I.S.S. Enterprise, and manipulate the Imperial Starfleet into working toward a more civilized universe.
When a landing party beams down to the planet Gamma Trianguli VI, they find what appears to be an idyllic paradise. They quickly discover, however, that the planet is deadly, sporting plants that shoot thorns, rocks that explode, and incredibly accurate lightning bolts.Review
With a much reduced party, they encounter the planet's inhabitants. They are a peaceful, child-like people who call themselves the "Feeders of Vaal." They dress in flowers and bright paint, never reproducing because they don't age or die. Each day they "feed" Vaal offerings of food. Vaal seems to be a large serpent's head carved of rock, but is actually the terminal for an advanced, underground computer. Seeing Kirk and his party as a threat, Vaal takes them prisoner and tries to pull the U.S.S. Enterprise from orbit.
Kirk realizes that by depriving Vaal of the natives' daily offerings of food, the computer won't be able to convert the offerings into reaction mass. Thus weakened, Kirk uses the U.S.S. Enterprise's phasers to destroy Vaal. This leaves the natives on their own to discover birth, death, and the everyday ways of life.
Sent to investigate the destruction of several planetary systems, the U.S.S. Enterprise discovers a crippled starship, the U.S.S. Constellation, floating in space. Commodore Matthew Decker is the only one left on the ship. Kirk and Scotty remain on board the Constellation to try and repair the starship, while McCoy beams Decker aboard the U.S.S. Enterprise.Review
Decker informs the crew that a giant robot ship, a planet-eating machine made by a long-dead alien race, is roaming the galaxies, consuming all in its path for fuel, including whole planets. When Decker challenged it, the "berserker," as he calls it, attacked. Decker beamed his entire crew to the planet's surface below, only to have the robot consume that planet, killing the Constellation's entire crew.
When the "berserker" returns, Decker, consumed with guilt over the loss of his crew, pulls rank on Spock and takes control of the U.S.S. Enterprise. He seems determined to destroy the machine, even at the cost of another ship and crew. Kirk, still on board the Constellation, contacts Spock and supports his claim that Decker is exhibiting suicidal behavior and is therefore unfit to command. Thwarted, Decker steals a shuttlecraft and flies it down the 'throat' of the giant robot ship, killing himself.
Realizing that Decker's idea, on a larger scale, might work, he sets the Constellation to self-destruct and send it after Decker's shuttlecraft. Due to a transporter glitch, Kirk barely makes it back to the U.S.S. Enterprise before the Constellation explodes, destroying the planet killer in its path.
On the planet Pyris VII, two beings known as Korob and Sylvia have been sent on a mission of conquest by their home world. Using a matter transmuter, they assume human form to welcome the U.S.S. Enterprise landing party.Review
When one member of the initial landing party returns to the ship dead, Kirk, Spock and McCoy beam down to find Scotty and Sulu transformed into mindless zombies. Sylvia and Korob appear as witch and warlock and use scare tactics to keep the officers from investigating the planet and their motives. Kirk, Spock and McCoy are taken prisoner and shown examples of Korob and Sylvia's "powers," which includes heating a small model of the U.S.S. Enterprise over a flame and having the heat transfer to the orbiting ship.
Sylvia takes an interest in Kirk and decides to abandon her original mission in order to learn about human feelings and experiences. When she finds out the captain is merely using her to gain an advantage, she becomes furious and retaliates.
Korob ultimately helps the crew to escape, but Sylvia turns into a giant black cat and crushes him. Kirk then uses Korob's wand transmuter to destroy Sylvia's source of power - her amulet - before smashing the wand. Their powers gone, the aliens revert to their true form - fragile blue creatures who quickly die in the planet's atmosphere. With their demise, Scotty and Sulu return to normal and the landing party beams back to the U.S.S. Enterprise.
Norman, an android pretending to be a member of the U.S.S. Enterprise crew, takes control of the starship and her crew, taking them to an unnamed planet where Kirk discovers an old nemesis - Harry Mudd.Review
Fleeing from his most recent criminal exploit, Harry crash-landed on the planet, which is inhabited by androids designed by a long-extinct race. At first their desire to fulfill his every need seemed like paradise, but Harry soon realized that precluded him ever leaving the planet. So, sending Norman to capture the U.S.S. Enterprise, Mudd hoped to trade the starship's crew for his own freedom.
The androids, however, want to use the U.S.S. Enterprise as a vehicle to populate the universe, serving mankind and protecting them from themselves. Unwilling to spend their lives on the strange planet, waited on by machines, Kirk and company set about finding a way out. It is not without temptation, however.
Spock is shown what is supposedly the control center for all the androids ... a veritable electronics dream come true. McCoy is given an extensive lab, set up to do all the research he's ever wanted to do, while Scotty is shown the technical machine shop of his dreams. The androids offer Uhura eternal youth and beauty while Chekov contemplates a planet filled with beautiful young women.
In the end, however, the crew bands together in an attempt to thoroughly confuse and, ultimately, short-circuit them. Through a series of illogical and very funny antics, the U.S.S. Enterprise crew and Mudd cause Norman, the central control for all the androids, to have an electronic "nervous breakdown."
Instead of granting Harry Mudd his freedom, Kirk leaves him on the planet with the remaining androids ... including many fashioned in the image of his shrewish wife, Stella, until he mends his ways.
Assistant Federation Commissioner Nancy Hedford has become ill while trying to stop a war on Epsilon Canaris III. The shuttlecraft Galileo is assigned to take her to the U.S.S. Enterprise, where she will receive treatment for the otherwise fatal Sakuro's disease.Review
En route, the shuttlecraft is pulled off course by a mysterious, cloud-like entity. Deposited safely on the planet Gamma Canaris N, Kirk and his party meet Zefram Cochrane, the scientist that discovered warp drive over 100 years before. But Cochrane appears young and vital, despite his age. The cloud-like creature, whom Cochrane calls the "Companion," has kept him young and handsome over the years. The Companion captured the Galileo in order to give Cochrane human companionship.
The Companion prevents Spock from repairing the disabled shuttlecraft and Kirk is worried that Nancy Hedford will die before they can get her to the U.S.S. Enterprise for treatment.
By using a translating device, Kirk discovers that the cloud entity has a female personality and is in love with Cochrane, who doesn't care for that idea at all. He's fallen in love with Nancy Hedford and agrees to help destroy the cloud creature so that they can save Nancy's life. When that attempt fails, the cloud creature enters Nancy's body, saving her life, healing her. In this way, the Companion can know human love with Cochrane and Nancy Hedford's life can be saved. With the Companion no longer holding him on the planet, Cochrane is free to leave, but decides to remain with what is now Nancy/Companion. As the landing party departs, Cochrane and his new mate contemplate children and a normal life span.
The U.S.S. Enterprise is appointed to transport ambassadors from many worlds to the Babel Conferences. Among those aboard are Ambassador Sarek of Vulcan and his human wife, Amanda - Spock's parents.Review
Keeping peace aboard his ship is complicated for Kirk by an unidentified vessel following the U.S.S. Enterprise and high tensions running among delegates on board. At a cocktail party, Ambassador Gav, a Tellarite, quarrels openly with Sarek about the admission of Coridan into the Federation. When Gav is later murdered, circumstantial evidence points to Sarek. The strain of such an accusation causes Sarek's already existing heart condition to worsen and he has the Vulcan equivalent of a heart attack. McCoy battles with less familiar Vulcan physiology to try and correct the damage. Spock is needed as a blood donor for the operation.
When Kirk is attacked by Thelev, an Andorian, Spock assumes command of the Enterprise, and refuses to participate in McCoy's operation on his father. The Vulcan insists that they identify and stop the vessel that is following them. Kirk fakes recovery and returns to the bridge, freeing Spock to go to the sickbay and assist in his father's surgery. On the bridge, Kirk must deal with the unknown ship, now in contact with someone on board the U.S.S. Enterprise. A search uncovers the fact that Thelev is not Andorian, but a surgically altered Orion, put on board to disrupt the Babel Conference.
The unknown ship attacks the U.S.S. Enterprise and is defeated. Rather than be captured, it destroys itself and Thelev commits suicide. With Spock available for the blood transfusion, Sarek's operation is a success and he recovers. Father and son make peace, realizing they have a common bond that transcends their differences. Kirk returns to sickbay for treatment of the knife wound caused by Thelev and McCoy gets the last word.
Sent to the planet Capella IV to negotiate a mining treaty, Kirk and a party beam to the surface. They find the Capellans to be warlike and tradition-bound people. Kirk also finds that a Klingon agent, Kras, has gotten there before them and established an agreement with some of the planet's rebels who kill their leader, Akaar, and take over. Akaar's widow, Eleen, is willing to forfeit her life, as custom demands, because she carries the child that will be the next leader, or Teer.Review
Kirk convinces her to escape and they hide in the hills beyond the city. While the landing party evades pursuit, a Klingon warbird prevents the U.S.S. Enterprise from helping its people.
When Eleen goes into labor, McCoy delivers the child. Eleen, however, hits the doctor over the head with a rock, knocking him out, and returns to the Capellans. She tells them that the landing party and the child are dead. The Klingon decides this is the time to take control and begins to attack the Capellans.
Arriving on the scene, Kirk and Spock try to use primitive bows and arrows on the Klingons which wound, but do not stop. Maab, the new Teer, draws the Klingon fire while his lieutenant kills him. Eleen names her son Leonard James Akaar, after Kirk and McCoy, and as her son's regent until he comes of age, signs the mining treaty with the Federation.
On the way to Starbase 10, the U.S.S. Enterprise stops to deliver supplies to the colonists of Gamma Hydra IV. A landing party consisting of Kirk, Spock, McCoy, Scott, Lieutenant Galway and Chekov beam to the planet's surface. They find that accelerated aging has taken place, killing most of the colonists. Chekov is terrified when he discovers the first body. The only survivors, an elderly couple who claim to be in their twenties, die shortly after meeting the Enterprise crew. When the landing party returns to the Enterprise, the aging acceleration begins to affect each of them - except Chekov, who remains curiously immune. While Kirk wants to stay in orbit around Gamma Hydra IV until a cure can be found, one of his passengers, Commodore Stocker, wants to proceed to Starbase 10 where he feels the best medical aid can be obtained.Review
The senior officers succumb to the effects of old age and soon Kirk is unable to command, as are Scotty and Spock. Command falls to Commodore Stocker, who, while an efficient desk officer, has no deep space training. Thinking he will save time, Stocker plots a course through the Romulan Neutral Zone on his way to Starbase 10. The Romulans are waiting and begin an attack.
Stocker, panicked and inexperienced, has no idea what to do. As the Enterprise is surrounded, McCoy comes up with an antidote to the aging sickness ... adrenaline. Chekov, he explains, wasn't affected because his fear at finding the bodies on Gamma Hydra IV had already kicked his natural adrenaline into high gear.
McCoy restores Kirk to normal in time to save the ship by reusing his famous "corbomite" bluff and telling the Romulans that the Enterprise would destroy anything within a 200,000 kilometer radius. McCoy distributes the antidote and restores everyone to their normal state.
Eleven years ago, the U.S.S. Farragut encountered a deadly cloud creature with vampire-like tendencies. James T. Kirk was on board the Farragut at that time as they entered the region of Tycho IV. The creature killed the ship's commander, Captain Garrovick, and half the crew by draining their red blood cells. To this day, Kirk feels guilt at having hesitated before firing at the creature - even though his phaser blast had no effect.Review
On his way to deliver necessary medical supplies, Kirk encounters what he believes is the same blood-sucking entity. He pursues it, against orders, determined to destroy it before it kills again.
A landing party beams down to the surface of Argus X, where the creature has taken refuge. In the party is the son of Kirk's former captain ... Ensign Garrovick. Garrovick spies the creature and, like Kirk 11 years before, hesitates before firing. The creature escapes and Kirk blames Garrovick for the resulting death of a crewman.
The creature leaves the planet with the U.S.S. Enterprise in pursuit. When Kirk fires on it, the creature turns and enters the starship. Fortunately, its first victim is Spock and, after tasting his copper-based Vulcan blood, flees toward its home world, Tycho IV. Fearing the creature will reproduce and, at the very least, kill others, Kirk and Garrovick prepare a trap with a matter/antimatter bomb and human blood. They lure the creature to take the bait and beam aboard the Enterprise as the creature is killed in the resulting explosion.
Kirk and McCoy decide to take Scotty, who is recovering from a head wound accidentally caused by a female crew member, to a nightclub on the planet Argelius II. Scotty becomes infatuated with a lovely dancer at the club and they leave together. In the meantime, Kirk and McCoy decide to sample some of the planet's other pleasures and leave.Review
A scream sends them to a foggy alley to find the dancer dead with Scotty holding a bloody knife. McCoy suggests that perhaps Scotty's subconscious distrust of women since his accident has manifested itself in murder.
Hengist, the local authority, wants to arrest Scotty, but Kirk intervenes and seeks the help of a priestess of an old psionic cult. Unfortunately, she's killed and once more the blame seems to fall at Scotty's feet. Before she dies, the priestess says that something with an insatiable hunger and hatred of women is present in the room. Scotty still claims to have amnesia during the time when the women were killed.
In the end, the entity turns out to be an ancient life form, Redjac, previously known on Earth as Jack the Ripper. It now appears in true form: a noncorporeal vampire who thrives on others' fear. It preys on women because they are more easily frightened. It has been living in the body of Hengist and, when discovered, kills Hengist and flees to the U.S.S. Enterprise.
McCoy administers tranquilizers to everyone on board so that the creature cannot evoke fear. Enraged, it is forced to return to Hengist's body. Kirk, knowing this would happen, beams it into space at maximum dispersal, where it will die for lack of nourishment.
When the U.S.S. Enterprise receives a top-priority order to protect a shipment of quadrotriticale grain on Deep Space Station K-7, Kirk is irritated to be guarding a shipment of "wheat." But the shipment is meant for famine-struck Sherman's Planet, and Klingons are taking shore leave on the space station. Adding to Kirk's irritation is Federation Undersecretary for Agriculture, Nilz Baris, and his pesty assistant, Arne Darvin, who inform Kirk that Starfleet Command is afraid the Klingons may try to steal the grain.Review
Another problem arises when a space trader, Cyrano Jones, gives Uhura a purring ball of fluff known as a tribble. Charmed by the creature, Uhura takes it back to the Enterprise. However, as McCoy soon learns, tribbles are born pregnant and the more they eat ... and they eat constantly ... the more they multiply. Soon the starship is overrun by the furry creatures.
Kirk soon finds that the bins that were once full of the precious quadrotriticale are now full of dead tribbles. The grain has been poisoned by a Klingon agent disguised as the Undersecretary's assistant, Darvin. His true identity is exposed when Kirk discovers that tribbles don't like Klingons (and vice-versa) and squeak whenever they're in near proximity. The Klingons leave the space station and Scotty rids the Enterprise of the tribbles by beaming them aboard the departing Klingon ship where, as he tells Kirk, " ... they'll be no tribble at all."
During a routine transport to a planet, Captain Kirk, Lieutenant Uhura and Ensign Chekov are intercepted and abducted by a powerful and distant transporter beam. Arriving, literally, flat on their backs on a planet called Triskelion in the M-24 Alpha star system, the are immediately attacked by beings from several different species, each of them wearing a collar around their necks.Review
Kirk and his crew mates have been brought to this planet to fight as gladiators in combat games in order to entertain and provide exciting gambling for the disembodied entities called the "Providers." Each assigned a "drill thrall" of their own, Kirk and his companions are collared as well, which asphyxiate those who are disobedient to the Providers.
On board the U.S.S. Enterprise, Spock, aware that the crew members are missing, attempts to locate them, and eventually finds the origin of the beam. Upon its arrival, the crew of the starship is also taken captive by the Providers.
With the ship and his entire crew at stake, Kirk makes a final wager to the Providers which they cannot resist: himself against three drill thralls on the condition that if he wins, all the drill thralls go free and are taught how to live for themselves again. If Kirk fails, he promises himself and the entire crew as the most entertaining fighters they've ever seen.
Kirk beats the three drill thralls and wins the wager, and the Providers set all the thralls free and permit the U.S.S. Enterprise and her crew to leave also.
The planet Sigma Iotia II's last visit by the Federation was by the U.S.S. Horizon - a hundred years before. Realizing the lapse in monitoring the planet, the Federation sends the U.S.S. Enterprise to observe the progress of Iotia's population.Review
Beaming down to the planet's surface, Kirk, Spock and McCoy are surprised to see a much different society - an Earth-like 1920s gangster culture - than was reported by the U.S.S. Horizon crew. Bodily seized, the landing crew are taken before one of the major planetary leaders, mobster Bela Oxmyx. Wishing to unite the population under his rule, Bela offers Kirk "a piece of the action" in exchange for the technologically advanced weapons of the U.S.S. Enterprise.
Meanwhile, the other lead gangster, Jojo Krako, has his own idea about being the head mobster and captures the Enterprise officers. Struggling to gain the upper hand in this comical power struggle, Kirk creates a diversion ... a little card game known as fizzbin. Without knowing the nuances of the culture, Kirk and Spock try to accomplish their mission when Kirk attempts to drive a car and Spock strives to speak in gangster slang.
Finally, Bela Oxmyx is given a display of the Federation's power when he is beamed aboard the Enterprise and held hostage in the transporter room. Arranging a meeting between the two antagonists, Kirk is successful in uniting the two gangs in a loose system of government with the Federation as Godfather ... for a piece of the action, of course. Furthermore, upon discovering a book - "Chicago Mobs of the Twenties" - the U.S.S. Horizon crew left behind 100 years before, Kirk and Spock finally understand how the highly imitative Iotians reinvented their entire society.
Back aboard the U.S.S. Enterprise, Kirk notices McCoy unusually drawn and worried. When questioned, McCoy is forced to admit that he thinks he left his communicator on Sigma Iotia II, leaving him to wonder what type of planetary society the next Federation visit will find ...
The U.S.S. Enterprise is en route to Starbase 6 for shore leave when Uhura receives a jumbled message from which all she can make out is a sector coordinate and the name U.S.S. Intrepid, a starship manned entirely by Vulcans. Suddenly, Spock shudders with pain and reports that the Intrepid just "died."Review
Kirk gets orders to head to Sector 39J because all contact has been lost with solar system Gamma 7A and with the Intrepid, which was investigating it. As the Enterprise changes course, long-range sensors show that the solar system, and its billions of people, are dead.
Approaching its destination, the U.S.S. Enterprise encounters a strange dark area in space. Kirk launches a probe. Seconds later, the crew hears a high-pitched whine throughout the ship, rendering half the people on board ill, and causing some to faint. Spock speculates that the phenomenon is some form of energy that is probably responsible for the death of the system inhabitants and the Intrepid crew. Kirk decides to move closer, and the crew hears the whine again. This time when they recover, the stars seem to have vanished. Spock reports that the noise was produced when the Enterprise passed through a boundary layer, and that they are surrounded by a field that is draining their mechanical and biological energy. McCoy confirms this when he reports from sickbay that everyone on the ship is dying.
Attempts by Scotty to recalibrate the engines and break free from the dark zone fail, and in fact the ship's expenditure of energy attracts an enormous amoeba-like creature approximately 18,000 kilometers in length. McCoy identifies the creature as an incredibly simple, single-celled organism which feeds on energy, but he needs more data to save the ship. He and Spock each volunteer to take a shuttle to investigate the creature - what would most certainly be a suicide mission - and Kirk decides to send Spock.
Spock takes the shuttlecraft through the creature's membrane and moves toward its nucleus. He reports that the creature appears to be ready to reproduce. He loses voice contact but manages to continue transmitting data.
Kirk and McCoy determine that if the creature begins to reproduce, it will spread rapidly and pose a serious threat to the galaxy, so it must be destroyed. But the Enterprise only has enough power left to survive for an hour.
Kirk and McCoy realize they have to use the U.S.S. Enterprise as an "antibody." Kirk orders the ship to punch its way into the giant creature and set a course for the nucleus. An antimatter charge is attached to a probe with a seven-minute delay. As soon as it is lodged in the nucleus, the Enterprise backs away at full impulse. There are only a few seconds to spare, but then they detect Spock's shuttle. Kirk locks two tractor beams onto the shuttle, even though doing so delays their escape. But when the antimatter explosion ruptures the creature's membrane, both ships are thrown to safety.
Captain Kirk leads a survey mission to a peaceful, primitive planet which he visited 13 years before as a lieutenant. He is dismayed to see a group of villagers armed with flintlocks, weapons they shouldn't have at their current stage of development. The villagers ambush the landing party and wound Spock. Returning to the U.S.S. Enterprise, Spock is put under the care of Dr. M'Benga, who once interned in a Vulcan ward. M'Benga tells McCoy they've done all they can for Spock, and that he has to recover on his own.Review
Meanwhile, a Klingon vessel is detected in orbit around the planet, and Kirk orders Chekov to keep the Enterprise out of sensor range while he returns to the surface. He'll be looking for Tyree, the tribal leader he befriended years earlier. Minutes after Kirk and McCoy beam down in native clothing, they are attacked by a mugato, a white apelike creature with poisonous fangs, who bites Kirk before McCoy can kill it with a phaser. They can't return to the Enterprise, so Kirk tells McCoy that Tyree's people have a cure for the mugato poison.
Some hill people find Kirk and McCoy and take them to their caves, informing them that Tyree is now their leader, and his wife, Nona, knows how to help Kirk. But Tyree and Nona are currently on a scouting mission. Nona is using drugs to keep Tyree devoted to her, and she urges him to acquire "firesticks" for their people, but being a devoted pacifist, he refuses. Informed about Kirk, Nona heads back to the caves, where she sees McCoy using his phaser to heat some rocks. Nona is intrigued, and wants to know more about their guests. Nona treats Kirk by cutting her hand and pressing a mahko root against Kirk's wound. She collapses but Kirk recovers. Now, according to legend, Kirk will be unable to refuse Nona anything.
Meanwhile, on the Enterprise, Dr. M'Benga has informed Nurse Chapel that Spock is in a state of self-induced hypnosis to heal his own injuries. When Spock's readings fluctuate, M'Benga is pleased, and tells Chapel that if Spock regains consciousness she is to do whatever the Vulcan asks.
Tyree tells Kirk and McCoy that the firesticks first appeared nearly a year ago, but assumes the villagers have been making them - he hasn't seen any strangers. Kirk asks him to take them to the village under cover of dark. Nona joins them and implores Kirk to help make Tyree a powerful man, but the captain says he will not interfere.
Tyree leads Kirk and McCoy into the village, where they find a forge containing clear evidence that Klingons are involved. They watch in hiding as the villager's leader, Apella, enters with a Klingon. Kirk and McCoy overpower them, take a flintlock and escape with Tyree's help.
Spock regains partial consciousness and demands that Chapel strike him. She does so hesitantly at first, but at Spock's insistence she slaps him harder and harder, until Scotty walks in and stops her, not knowing he's endangering Spock by doing this. M'Benga finds out what's happening, rushes over and slaps Spock violently until he is fully conscious. Spock thanks him for bringing him out of his hypnotic state.
On the planet, Kirk teaches Tyree and his people how to fire the stolen flintlock. McCoy points out that he is corrupting the hill people's society, but Kirk replies that the Klingons left them no choice - in order to bring equity back between the hill people and the villagers, he has to provide equal weapons. McCoy is horrified, but has no alternative solution. Realizing Tyree is hesitant to arm his people, Kirk hopes that Nona can convince her husband to fight. When he approaches her, she uses the same drug on him that she used to seduce Tyree. Kirk falls under her spell. Tyree sees what's happening and aims the flintlock at his wife, but he cannot bring himself to shoot. He throws the weapon away in disgust and walks off.
Suddenly, a mugato attacks Kirk and Nona. After a struggle, Kirk is forced to destroy the creature with his phaser. Seeing her opportunity, Nona knocks Kirk out and takes the phaser. Tyree and McCoy find Kirk and revive him, while Nona runs into a patrol of villagers and offers them victory by using Kirk's phaser. But the villagers attack and kill her. Tyree and Kirk rush in and overpower the villagers. When Tyree learns that Nona is dead he takes up the rifle and tells Kirk he needs more weapons. McCoy retrieves Kirk's phaser, and Spock contacts them from the ship. Kirk orders Scotty to manufacture a hundred flintlocks - they are making serpents for the Garden of Eden.
The U.S.S. Enterprise tracks a mysterious SOS to an ancient planet presumed long dead. The crew hears a voice from a telepathic being named Sargon, who asks Kirk to beam down to the surface. When Kirk, Spock and McCoy arrive in the transporter room, they find that Dr. Ann Mulhall has also been summoned. Sargon operates the transporter and leaves the security guards behind.Review
The landing party find themselves in a vault, and encounter a glowing sphere that identifies itself as Sargon. He explains that his people were destroyed in a cataclysmic war half a million years ago, and that he once had a body, but now is only pure thought. Sargon insists that he and two others of his kind need to "borrow" the bodies of the Enterprise officers long enough to construct new artificial ones. Sargon briefly takes control of Kirk's body, and leads the landing party into another chamber holding two rows of spheres, which are all now dark except for two. Those two beings are Sargon's wife, Thalassa, and his former enemy, Henoch. Sargon explains that this is how they stored their minds after the war, laying in wait for someone to find them. But by now Kirk's body is weakening, so Sargon returns control to the captain.
Scotty beams the three receptacles aboard and McCoy monitors the transfer process in Sickbay. Sargon takes Kirk's body, Thalassa takes Mulhall's, and Henoch takes Spock's. They are all overwhelmed by the pleasure of having physical bodies after so many years. Almost immediately, though, Henoch plots to kill Sargon in Kirk's body. While Sargon leads the effort to build androids for them to occupy, Henoch attempts to lure Thalassa into agreeing that they should keep their host bodies.
Henoch telepathically forces Nurse Chapel to poison Sargon (in Kirk's body) and then destroys the globe that houses Spock's mind. McCoy and Nurse Chapel keep Kirk's body on life support, but his mind is still trapped in Sargon's receptacle. Henoch has completed an artificial body for Thalassa, but she refuses to transfer her consciousness into it. Instead, she goes to sickbay and offers McCoy a chance to save Kirk in return for keeping the human body. McCoy refuses, so she attacks him with her thoughts. But then she realizes what she's doing and breaks off her assault. Suddenly, she and McCoy hear Sargon's voice - he transferred his mind into the ship's computer, and he has a plan. Chapel arrives, and Thalassa orders McCoy out of the room. The room shakes, and a few seconds later Chapel walks out. When McCoy rushes back in, he finds Kirk and Mulhall restored to normal, and all the receptacles destroyed. Kirk orders McCoy to prepare a hypo with a deadly injection - Spock's mind is now dead, so now they must destroy Henoch.
By now Henoch has taken control of the Enterprise. On the bridge, McCoy attempts to inject him, but Henoch stops him and orders Nurse Chapel to inject the Doctor. She takes the hypo, but injects Spock's body instead. Henoch tries to move to another body, but Sargon stops him, and he falls to the floor. Chapel staggers, and Spock stands up. It turns out that Spock's consciousness had been transferred into Chapel's body, and that the injection wasn't really deadly - Sargon had manipulated the Doctor to believe it was because Henoch could read McCoy's thoughts.
Sargon and Thalassa realize that they cannot live in the physical world, but before they depart to roam the universe in their noncorporeal state, they inhabit Kirk's and Mulhall's bodies one last time so they can share a kiss.
The U.S.S. Enterprise is sent to planet Ekos to investigate the disappearance of an old Academy professor of Kirk's - historian John Gill. The Enterprise is attacked by an armed probe with a thermonuclear warhead, technology that is too advanced to be from Ekos or the nearby Zeon. Captain Kirk destroys the probe before it can do any damage, then takes the ship into orbit around Ekos out of range of the planet's detection devices. Spock tells him that, according to their records, the Ekosians are primitive, warlike people in a state of anarchy; Zeon has a relatively high level of technology, and its people are peaceful.Review
Kirk decides to beam down to Ekos with Spock; and Dr. McCoy fits them both with subcutaneous transponders. Scotty is ordered to use the transponders to locate and beam them back if they fail to make contact in three hours. When Kirk and Spock arrive on the planet's surface, a Zeon man urges them to hide. They watch as the man is arrested by officers wearing swastika armbands. Spock reminds Kirk that the Prime Directive prohibits them from interfering.
A viewscreen in the street plays news footage revealing that Ekos has adopted a military regime similar to that of Nazi Germany, and is now at war with Zeon. Kirk is puzzled that another planet could independently develop a culture identical to one that once existed on Earth. They watch a female Nazi officer called Daras receive a medal of honor, and learn that the planet is committed to the death of Zeon. The broadcast ends with a salute to the Führer - John Gill.
Kirk and Spock steal uniforms and assume the identities of Nazi officers in order to infiltrate government headquarters, but they are arrested before they can find Gill. Their phasers and communicators are confiscated, and they are tortured and interrogated. In jail they meet Isak, the man they saw being arrested earlier. Isak tells them that the Nazi movement on Ekos began when Gill arrived a few years earlier, and it is only a matter of time before Ekos invades Zeon.
Spock uses his subcutaneous transponder to make a crude laser that cuts open the cell door. They find their communicators in pieces, but Spock takes one and they escape. Isak takes Kirk and Spock to an underground resistance group led by his brother Abrom. Kirk explains to Abrom that he needs to find John Gill in order to end the war. But then the resistance cell is infiltrated by Daras, the high-ranking Nazi woman seen in the newsreel, who shoots Abrom. Kirk and Spock overpower and disarm her, but then they learn Daras is really a member of the underground, and the shooting was a ruse to test their loyalty. Isak and Daras explain that Deputy Führer Melakon is the one in command. Gill sees no one, but he is making a speech from the Chancellery. Daras agrees to help Kirk, Spock and Isak get past the guards. They dress as members of a Gestapo film crew and make their way into the headquarters. Isak wants Kirk and Spock to kill Gill as soon as possible, but Kirk refuses.
They find Gill in a booth surrounded by guards. Spock observes that he seems to be ill, or perhaps drugged. When Spock contacts the Enterprise with a repaired communicator, Kirk tells McCoy to put on a Nazi uniform and beam down. Watching Gill make his speech, McCoy confirms that he has been heavily drugged. Kirk, Spock and Isak overpower the guards so that McCoy can administer a stimulant to Gill, but he fails to revive him. Spock performs a mind probe on Gill, which brings him to consciousness. Gill tells them he used the example of Nazi Germany to bring order to Ekos. It worked at first, but then Melakon seized control, drugged Gill to use him as a figurehead, and started the war with Zeon. With another, potentially fatal dose of stimulant, Kirk keeps Gill conscious so he can make another broadcast from the booth. Gill announces that he has recalled the fleet and that the war must stop; he also tells the people that Melakon is a traitor. Melakon opens fire on the booth, and Isak shoots him. Gill is fatally wounded, but before he dies, he tells Kirk he was wrong to break the Prime Directive. But now he hopes the damage has been undone, and the Ekosians and Zeons will now work together.
When the U.S.S. Enterprise answers a distress call from a small planet, the landing party is captured by a group of agents from the Kelvan empire, located in the distant Andromeda galaxy. The Kelvans' purpose is to find planets suitable for colonization. However, their own ship was destroyed and now they need the Enterprise to make the 300-year journey home. To utilize the starship, the Kelvans - huge, tentacled creatures - take on human form. After several attempts at escape, Kirk accepts his fate and agrees to let the aliens take over his ship. The Kelvans use their technology to transform all but essential Enterprise personnel into small "cubes" which, unless broken or damaged, can be restored to human beings.Review
Recognizing that the Kelvans, in their new human bodies, are discovering human sensation and emotion, the remaining crew attempts to foster dissent amongst the aliens: Scotty succeeds in gettting one of them drunk, McCoy injects an irritant into another, and Kirk makes romantic overtures to the Kelvan leader's woman. With the Kelvans thus distracted, Kirk and the crew are able to regain control of the ship.
Kirk points out to Rojan, the Kelvan leader, that the Kelvans are already becoming less like they were before by encountering the humans. In 300 years, their descendants will be so human-like that they won't be able to live among their people on Kelva. Rojan sees the logic in his argument and sends a robot probe to Kelva, reporting what has happened. Pledging to restore the Enterprise crew, Rojan accepts Kirk's offer that the Enterprise find the Kelvans a Class-M planet to colonize.
The U.S.S. Enterprise finds a crewless starship, the U.S.S. Exeter, in orbit around the planet Omega IV. The boarding party from the U.S.S. Enterprise contracts a virus that may have killed the Exeter's crew, but the biosphere on Omega IV is found to contain an immunity. The party is beamed to the surface.Review
There they discover Captain Tracey, the commander of the U.S.S. Exeter. He has been violating the Federation's Prime Directive by interfering in the politics of the natives, using his phaser to protect the asian-like villagers, the Kohms, against the barbarian raiders, the Yangs. Tracey demands that Kirk supply him with more phasers, which Kirk refuses to do.
The Yangs capture the Kohms village and the U.S.S. Enterprise crew learns that these people are possibly descendants of Earth's Communist Chinese who left Earth in the last years of the 20th Century. The Yangs mouth a distorted version of the United States Constitution, which are their 'holy words' and which Kirk recites, gaining their confidence. Prolonged exposure to the planet's atmosphere cures the landing party and, with Captain Tracey under arrest, they return to the U.S.S. Enterprise.
The U.S.S. Enterprise is chosen to be the test ship for the new M-5 multitronic computer system, a computer meant to be able to run a starship without human intervention. Also aboard for the test is Dr. Richard Daystrom, the inventor of the M-5 and an obsessive and unstable individual.Review
Initially the M-5 performs well, but when it decides to destroy a robot freighter, Kirk orders the test canceled. The M-5, however, protects itself and makes it impossible for it to be disconnected. The computer becomes increasingly erratic, a result of Dr. Daystrom's decision to impress his engram onto the computer as part of its programming. Starting a scheduled war games drill, M-5 uses the full arsenal of the U.S.S. Enterprise to attack four other Federation starships.
In a last-ditch appeal to the M-5, Kirk makes the computer realize that it has committed the sin of murder. Since Dr. Daystrom would be ethically abhorred at such an act, the M-5 is equally penitent and tries to commit suicide by leaving the U.S.S. Enterprise defenseless against a counter-attack by the remaining other starships. At the last moment, Spock and Scott are able to finish disconnecting the M-5 unit. Kirk keeps the shields down, gambling successfully that the attacking ships would not fire on an undefended vessel. Restoring communications next, the fleet is called off.
The U.S.S. Enterprise finds the wreckage of the S.S. Beagle, with no survivors, orbiting near the Planet 892-IV. When Kirk, Spock, and McCoy beam to the planet's surface, they find a dishelveled group of "sun worshipers" trying to escape being caught by the local authorities. They are captured, along with the landing party, and taken to the city which looks very much like Earth's ancient Rome.Review
They find that Captain R.M. Merrick of the Beagle has betrayed his crew, beaming them down to fight in the Roman-like gladiatorial games. Merik is First Citizen of the Empire and supposed close friend to the Proconsul, Claudius Marcus. Kirk realizes, however, that Merrick is being used as a lure to get more starship crews to 892-IV for the entertainment of its inhabitants.
When Kirk refuses to beam his crew down to die in the arena, Spock and McCoy are condemned to fight gladiators in the ring. The bout is being televised for the planet's enjoyment, but Scotty cuts off the planet's energy supply, spoiling their pleasure. When Kirk uses the confusion to free Spock and McCoy, Merrick sees how a true starship captain acts in the face of danger and uses his communicator to have Kirk, Spock and McCoy beamed aboard the U.S.S. Enterprise. For his treachery, Merrick is killed by the Proconsul.
Uhura, who has been monitoring the radio waves of the planet, realizes that the "sun worshipers" aren't talking about the sun in the sky, but of the "Son of God."
Sent back in time to find out how Earth managed to survive without destroying itself, the U.S.S. Enterprise inadvertently beams aboard a space traveler, Gary Seven, along with his black cat, Isis. Seven claims to be a 20th-century human raised and trained by unknown and unnamed aliens to prevent Earth from destroying itself. Before Kirk can determine whether or not the man is telling the truth, Seven escapes to the planet below. Kirk and Spock follow him to Earth. Meanwhile, Seven has tried to contact two fellow agents, who are discovered to have recently died in an auto accident. Instead, he contacts Roberta Lincoln, who becomes his reluctant cohort.Review
An orbital bomb is about to be launched by the United States and it is Seven's mission to make sure the rocket explodes somewhere over Asia, thereby frightening the governments into not launching future bombs into space.
When the rocket goes out of control, Seven barely succeeds in stopping it, despite Kirk and Spock's well-meaning interference. Before Kirk and Spock leave Earth, Kirk consults the Enterprise's computer records and informs Seven and Roberta that they have a very interesting future in the offing.