The Enterprise is in danger when Janice Lester, one of Kirk's former lovers, steals his body.
Kirk, Spock, and McCoy become trapped in the past of another world.
Kirk and Spock meet Abraham Lincoln and Surak of Vulcan and must do battle with some of history's most terrible villains.
The Enterprise picks up a group of space "hippies" looking for Eden.
While seeking a cure for a fever ravaging the Enterprise, Kirk and Spock encounter Flint, a hermit-like Earthman, and his beautiful young ward.
The Enterprise must deal with discorporeal cloud-like aliens who have already destroyed the inhabitants of a library planet and plan to eliminate the Enterprise crew if they cannot acquire a human host.
Kirk, McCoy, and Sulu are stranded on a barren planet where a mysterious woman attempts to kill them one at a time, while the Enterprise must travel halfway across the galaxy to rescue them.moreless
Kirk beams down on a diplomatic mission... and finds himself on an Enterprise where all the crew have vanished and only a mysterious woman resides.
The Enterprise finds itself host to two alien beings from the same planet, who share an intense and self-destructive hatred of each other.
The Enterprise must escort an alien princess to her marriage to seal an interplanetary alliance...but she becomes attracted to Kirk.
When a landing party investigating Scalos begins to vanish one by one, Kirk, Spock and McCoy try to find out what is happening before more of the crew disappears, until Kirk himself is abducted. Kirk finds the cause to be a group of endangered Scalosians who move faster than human sight or hearing can detect. They need to repopulate their species, and find that speeding human males up to Scalosian speed will meet their needs. Kirk must find a way to get a message to Spock and McCoy, who are working on a cure for the mystery "ailment," as well as stirring up fighting among the Scalosians, before they have control of the Enterprise.moreless
Kirk and his crew find themselves at the mercy of powerful individuals who possess mind-over-matter powers... and plan to use the Enterprise crew for their twisted entertainment.
When the Enterprise investigates the disappearance of another starship, the crew loses Kirk in a dimensional interphase and must deal with a hostile alien race while trying to recover him.
The Enterprise must deflect an asteroid on a collision course with an inhabited planet... but discover the asteroid is a spaceship with a population unaware of the outside world.
When the Enterprise brings aboard Klingon prisoners, an alien entity pits both sides against each other in an ever-escalating struggle.
Stardate 5630.7:...or is there in beauty no truth? Miranda Jones, a telepath who studied mental disciplines on Vulcan, arrives with Ambassador Kolos, a Medusan - an alien life form whose physical form is so hideous, humanoid life forms are driven insane if they look upon him. Also beaming aboard is Larry Marvick, one of the original designers of the Enterprise - and hopelessly in love with Miranda, although she has chosen to spend her life serving as a liaison between the Medusans and other humanoids. Miranda senses that someone is actively contemplating murder, and suspects Spock is envious of her once-in-a-lifetime mission - but even Miranda is unaware of the real would-be killer and their target.moreless
The Enterprise travels to a planet where a scientific team has killed themselves... except for the children, who begin to act oddly.
Kirk, Spock and McCoy beam down to a planet in the path of an oncoming asteroid. However, Kirk disappears and the Enterpriseis forced to abandon the search to stop the asteroid in time. Meanwhile, Kirk recovers consciousness but has no memories of his previous life, and is adopted by a local Amerindian tribe as their medicine chief and god.moreless
Captain Kirk becomes increasingly erratic and orders the Enterprise into Romulan space... where the ship is captured by a beautiful Romulan commander.
The Enterprise is intercepted by a starship of unknown design and a woman from the ship beams directly into the bridge and uses a device to render the Enterprise's crew unconscious. She then walks over to Spock... When the crew awakens, McCoy summons Kirk to sick bay and informs him that the alien visitor apparently removed Spock's entire brain without even performing surgery. After Spock's body is fitted with a device that allows McCoy to control the Vulcan's motor functions with a remote control, Kirk starts a search for Spock's brain, hoping it can be recovered and somehow returned to Spock before his body decays.moreless
The Enterprise encounters a planet whose culture is patterned on ancient Rome... and holds gladiatorial games that Kirk, Spock, and McCoy must fight in.
Starfleet uses the Enterprise to test a new super-sophisticated computer, but it soon develops a mind of its own.
The Enterprise investigates the disappearance of another starship and discovers a planet where the inhabitants are immortal... and engaged in a strange parallel of Earth's Cold War period.
The Enterprise's command crew must thwart an invasion by aliens from another galaxy who plan to conquer this one.
The Enterprise seeks out a historical researcher with whom the Federation has lost contact, and discovers he has contaminated a culture, remaking it into a near-duplicate of Nazi Germany.