Spectre of the Gun
When Kirk ignores a warning buoy guarding Melkotian space, the Melkots demand punishment for Kirk and company on their bizarre planet. In a 19th-century Earth "Wild west" town, Kirk and the others are forced to play the roles of the notorious Clanton gang.
Elaan of Troyius
Enterprise is told to transport Elaan of Elas to her marriage ceremony at the Planet Troyius, which will result in an alliance between the two hostile worlds. It sounds like a simple enough assignment, until one takes into account the fact that the woman has no interest in the marriage, the Klingons want to see the alliance fall apart and are doing what they can to make this happen, the Troyius ambassador is murdered and Kirk falls madly in love with Elaan due to the chemical reaction of her tears on his skin.
The Paradise Syndrome
When a planet is threatened by an asteroid, a landing party beams down to try and evacuate the population. an accident gives Kirk amnesia and he is eventually found by a tribe of Indians, who look upon him as a god. Referring to himself as Kirok, he takes a bride in Miramanee and is ultimately the victim of the changing mood of the crowd, who realize that he is actually human and not someone to be revered. This episode is marked by a particularly tragic ending in which Miramanee is killed, along with her and Kirk's unborn child.
The Enterprise Incident
Kirk appears to be suffering from a nervous breakdown and orders the Enterprise into forbidden Romulan territory. Suddenly the Enterprise is surrounded by three Romulan ships demanding Kirk's surrender! Aboard the enemy vessel, Spock denounces Kirk and appears to show interest in the Romulan female commander.
And the Children Shall Lead
the Enterprise retrieves a group of orphaned children on Triacus. A short matter of time later, it becomes obvious that they are being manipulated by "Gorgon, the Friendly Angel," who turns out to be something far more sinister. Kirk and company must make the children see him for what he truly is.
the Eymorgs steal Spock's brain to use as a power source on their planet, and the race is on for the Enterprise to retrieve it before his body dies. the less said about this one the better, though it's surprising that Gene Coon, under the name Lee Cronin, is credited with the teleplay.
Is There In Truth No Beauty?
the Medusans are a race of energy patterns deemed so horrifying to look at that they have a tendency to drive humans insane. One of their kind is taken aboard the Enterprise by Dr. Miranda Jones for transport, and amidst insanity and attempted murders, we learn that all things are not as they are initially perceived.
A pair of aliens named Lal and Thann capture Kirk, Spock and McCoy, and involve them in a series of experiments that include a mute woman named Gem, who has empathic abilities which allow her to absorbs the pain and suffering of others. the aliens are doing so in order to determine whether or not Gem's race is worthy of being saved from a forthcoming super nova, or if a neighboring planet is worthier to survive.
The Tholian Web
Kirk, Spock and McCoy beam aboard the U.S.S. Defiant, adrift in space, and find that her entire crew is dead. the Defiant is caught in an interphase between alternate universes, and although Spock and McCoy beam back safely, Kirk becomes trapped between dimensions! Then aliens called Tholians accuse the Enterprise of trespassing into their space and begin weaving an incredible energy web around the starship.
For the World is Hollow, and I Have Touched the Sky
the Enterprise discovers planet Yonada is on a collision course with an asteroid and Kirk, Spock and McCoy beam down to warn the Yonadans. But unknown to these people, their "planet" is actually a spaceship sent by their ancestors to colonize a new planet. the ship is controlled by the Oracle, an unrelenting computer, and all will die if Kirk and the others are unable to free the planet-ship from the Oracle's control! Day of the Dove
an energy force that feeds on anger, hatred and hostility arms both the Klingons and Kirk's people with swords and sets them at each other's throats on board the Enterprise. Kirk and his opponent, Kang, must come to grips with what exactly is putting them through this, and combat it before both sides are slaughtered.
the Enterprise proceeds to Platonius in response to a distress signal, and what they find are a race of people who have based their society somewhat on ancient Rome. the difference is that they have developed extraordinary telekinetic abilities which they use to control their jester, a dwarf named Alexander. What the Platonians eventually detail is that they want Dr. McCoy to remain behind to tend to them should they get ill. Kirk refuses to allow this, these self-acclaimed gods start trying to control them, forcing Kirk, Spock, Uhura and Nurse Chapel into somewhat humiliating positions. Additionally, they were basically the catalyst behind television's first inter-racial kiss.
Wink of an Eye
Responding to a call from Scalos, Kirk and company beam down to find the city deserted, except for insect-like buzzing sounds. Then a member of the landing party sips some water and vanishes! Back aboard the Enterprise, Kirk drinks coffee and also disappears! He finds himself in accelerated time, the love-slave of the Scalosian queen, who sabotages the Enterprise and plans to use Kirk to help repopulate her planet!
That Which Survives
While exploring unique geological conditions on an unnamed planet, Kirk, Sulu and McCoy confront the holographic image of a woman named Losira. She is actually a warning device left behind by an ancient civilization to repel their enemies, the Kalandans. Her "touch" is death, and it is up to the crew of the Enterprise to shut down the computers that continue to generate her lethal image.
Let That Be Your Last Battlefield
The Enterprise finds itself in the midst of a chase between an alien law enforcement officer named Bele and his prey, Lokai. Half the face of each man is white while the other half is black. the only difference is the side on which the particular color is. Bele reveals that, on their world, Lokai is a criminal and lower life form because his colors are on the wrong side. Ultimately Kirk makes the discovery that the aliens are sole survivors of their homeworld, the population having killed themselves.
Whom Gods Destroy
the inmates have taken over the Elba II asylum, and it is in that situation which Kirk and Spock are captured by former Starfleet captain Garth, who has acquired the power to change his shape at will.
The Mark of Gideon
Kirk attempts to beam himself down to the planet Gideon, but is shocked to find himself back on the Enterprise, with the difference being that he is the only person aboard. This turns out to be the work of the inhabitants, who have created an exact duplicate of the starship to trick Kirk. It seems that the planet is suffering from overpopulation because the citizens are disease free. Kirk, though, carries the remnants of a disease that nearly killed him. They want the captain to infect one of their people so that disease, and then death, will spread across the planet.
The Lights of Zetar
Lieutenant Mira Romaine, who Scotty has fallen in love with, is possessed by the lights of Zetar, a cloud-like being that is actually the collective existence of a now-dead race. Enjoying physical existence again, they decide to keep their human host at the expense of her own life.
The Cloud Minders
the Enterprise arrives at Ardana to obtain zienite, a cure for a plague on Merak II. What they find is a divided race, with the elite living in the city in the clouds while the "have-nots" mine the zienite mineral, and they seem quite insane. Kirk realizes that the gas of the mines is causing this madness and he sets about getting both sides to talk out their differences.
The Way To Eden
A group of space hippies attempt to take over the Enterprise so that they can be transported to the mythical world of Eden, a realm supposedly of paradise.
Requiem For Metuselah
While searching for a cure to a rare disease, Kirk, Spock and McCoy beam down to the surface of Holberg 917-G. There they are surprised to find a man named Flint, who turns out to be an immortal. Kirk falls in love with Flint's daughter, Rayna, and is horrified to learn that she is actually an android, as are all the "people" living there.
The Savage Curtain
the ultimate battle between good and evil as Kirk, Spock, President Lincoln and Vulcan pioneer Surak go up against mad scientist Zora, Genghis Khan, murderer Colonel Green and the Klingon that inspired the Empire, Kahless. the mediator is a rock creature named Yarmek, who is curious as to which side will prove victorious.
All Our Yesterdays
Kirk, Spock and McCoy beam down to Sarpeidon to rescue inhabitants before its sun explodes. But they arrive to find only the planet's librarian, who has helped all the others to safety via a time machine. When Kirk accidentally enters the past, Spock and McCoy attempt a rescue, emerging in a bitter ice age! Spock, now a throwback to earlier Vulcan times, falls in love with a beautiful woman and has no intention of returning to Kirk or the Enterprise!
Kirk finds himself the victim of Dr. Janice Lester's hatred. She was once romantically involved with the captain, and has been unable to assume a command of her own. Now she wants revenge and has found it in an alien device which is able to transfer her mind to Kirk's body and vice-versa.