While exploring the edge of the galaxy, the Enterprise encounters an energy barrier that gives two crewmen godlike powers.
The Enterprise encounters a vast alien ship that sets out to test them.
The Enterprise picks up a intergalactic conman, Harry Mudd, and three incredibly beautiful women who harbor a dark secret.
A transporter malfunction causes Captain Kirk to split into his "good" and "evil" selves, and a landing party will freeze to death if they don't merge the two back together.
Kirk and his crew are at deadly risk from an alien creature that feeds on the salt in a human body and can take on any form.
A strange alien substance causes the crew to act out their deepest inhibitions, while the ship plummets out of orbit.
Stardate 1533.6: The Enterprise picks up Charlie Evans, a young man who is the sole survivor of a transport crash. Little do they know he possesses extraordinary mental powers which will come to pose a threat to the ship and its crew.
Kirk pits the Enterprise against an invisible spaceship testing the Federation's defenses.
Nurse Christine Chapel is reunited with her old fiance on Exo III, but the scientist has plans for Captain Kirk and the Federation.
Kirk investigates an experimental facility for holding prisoners and finds a sinister scheme.
Kirk and a landing party are stranded on a planet due to a disease that causes any adult to die a painful death, and must deal with the local children who have survived.
Kirk is one of the last survivors who can identify a mass killer, who lurks among a Shakespearean troupe aboard the Enterprise.
Spock commands a stranded away team when their shuttlecraft is stranded on a planet with hostile natives.
Captain Kirk's career is at stake when he is put on trial for the loss of a crewman during an ion storm.
Spock kidnaps his former captain, the crippled Christopher Pike, and heads for a quarantined planet, putting his career and Kirk's life on the line.
Spock's court-martial continues as he attempts to justify his abduction of Pike, the theft of the Enterprise, and his heading for a planet declared forbidden by Starfleet.
The Enterprise crew take shore leave on a peaceful, pastoral planet... where their dreams and fantasies come to life.
The Enterprise finds itself at the mercy of a seemingly omnipotent being who fancies himself a 18th century Englishman.
When a mysterious alien race destroy an Earth colony, the Enterprise pursues but Kirk and the alien captain are forced to fight each other by powerful aliens.
Kirk and Spock encounter an alien named Lazarus who claims to be from an anti-matter universe.
The Enterprise collides with a black hole and is thrown back to Earth in the 20th century, where they must find a way back and erase any trace of their presence. Matters become complicated when they rescue an Air Force pilot and cannot return him without changing history... but if he disappears that will change history as well.
The Enterprise encounters a seemingly peaceful civilization run by a "benevolent" being named Landru... who intends for them to join his people.
The Enterprise arrives at a planet to establish diplomatic relations and finds itself in the middle of a "peaceful" war that threatens to destroy the ship.
The Enterprise picks up a crew of genetic supermen from the 20th century... and their leader, Khan, plans to create a new empire.
The Enterprise crew is trapped in paradise when they come to rescue colonists who have fallen to pacifying alien spores and become infected themselves.
Kirk investigates a series of grisly murders on a mining planet that are the work of a seemingly hostile alien creature.
The Federation and the Klingon Empire teeter on the brink of war as Kirk investigates Organia, a humble planet inhabited by pacifists that is unwittingly caught in the middle.
Kirk and Spock must travel into the past in order to correct a change that will alter history.
Kirk and the Enterprise must combat parasitic aliens.
When a landing party disappears and one man is beamed up dead, Kirk and Spock investigate and meet a pair of aliens who seem capable of performing magic.
When their shuttle is diverted to a planetoid, Kirk meets one of the pioneers of space flight, Zefram Cochrane.
Kirk, Spock, and McCoy land on a primitive planet to negotiate a mining treaty, but soon find themselves involved with intrigue and must flee with a pregnant woman into the surrounding mountains.
The Enterprise encounters an alien who claims to be the Greek god Apollo.
Spock must go to Vulcan in order to perform the Vulcan mating ritual.
The Enterprise must stop an ancient doomsday weapon that is capable of destroying entire worlds... and has already totalled one Constellation-class cruiser.
A serial killer stalks a planet... and Scotty is the prime suspect.
The Enterprise encounters an ancient Earth probe bent on the sterilization of all life.
Kirk attempts to assist a primitive people that are ruled over by a computer named Vaal.
Kirk and three of his officers are accidentally transported into a parallel "mirror" universe where violence, greed, and evil are commonplace.
A landing party, including the command staff, are infected with a disease that causes rapid aging and senility.
The Enterprise is taken over by a group of androids who are working for Kirk's old nemesis, Harry Mudd.
Kirk must defuse a Klingon scheme to destroy a grain shipment... and cope with a seemingly benign creature known as a tribble, which reproduces at amazing speed.
The Enterprise investigates the disappearance of a merchant ship crew on a planet ruled by a twentieth-century incarnation of ancient Rome.
Spock meets his estranged father when the Enterprise escorts a group of ambassadors to a conference on the planet Babel.
Kirk becomes involved in an arms race when the Klingons equip a native people with superior weaponry.
Kirk, Chekov, and Uhura are kidnapped and forced to participate in a series of gladiatorial games.
The Enterprise must deal with a creature from Kirk's past that feeds on human blood.
The Enterprise must destroy an enormous space amoeba before it reproduces and threatens known space.
The Enterprise travels to a planet suffering from cultural contamination from an earlier expedition - the inhabitants mimic the culture of 1930's gangland Chicago.
The Enterprise's command crew must thwart an invasion by aliens from another galaxy who plan to conquer this one.
The Enterprise discovers three discorporeal intelligences who seek their help in gaining physical bodies... but one of them has plans of his own.
The Enterprise seek out a historical researcher and discover he has contaminated a culture, rendering it into a near-duplicate of Nazi Germany.
The Enterprise is used 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 is sent on a mission back to Earth in the year 1968, where the crew encounters the mysterious Gary Seven, who claims to have been sent by advanced beings to save the planet.
When coming to an exaphobic isolationist planet, Captain Kirk and his landing party are punished for trepassing. They are sentenced to death in a surreal recreation of the Gunfight at the OK Corral with the landing on the losing side.
The Enterprise must escort an alien princess to her marriage to seal an interplanetary alliance... but she becomes attracted to Kirk.
Spock and the Enterprise crew race to destroy an asteroid threatening a primitive world where an amnesiac Kirk is proclaimed a god by its indigenous people.
An unusually tense and irritable Kirk orders his ship into the Romulan Neutral Zone, where it is promptly surrounded. Beamed to a Romulan ship, Kirk lies about the intrusion, then attacks Spock, who responds with a Vulcan death grip. While the female Romulan commander courts Spock, a secret mission unfolds.
The Enterprise travels to a planet where the members of a scientific team appear to have killed themselves. Their orphaned children are brought back to the ship, where they begin exhibiting odd behavior.
Kirk leads the Enterprise in pursuit of a mysterious alien woman after she beams aboard the bridge and steals Spock's brain.
The Enterprise hosts an alien ambassador whose outward appearance induces madness in humanoids. When Spock is driven mad after an unfortunate oversight, only the ambassador's jealous telepathic companion can save his mind.
On a planet doomed to destruction, Kirk, Spock & McCoy become involved with two aliens who use them as laboratory animals in a bizarre series of tests on an alien empath who may be the savior of her planet.
Captain Kirk finds himself trapped between dimensions on a disintegrating starship. The Enterprise crew works against time to rescue him as the Tholians weave a destructive energy web around their ship.
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.
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.
Invisible to humans due to their time-accelerated state, a group of aliens invade the Enterprise and attempt to abduct members of the crew to serve as breeding stock for their dying planet.
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.
The Enterprise finds itself host to two alien beings from the same planet, who share an intense and self-destructive hatred of each other.
Kirk and Spock investigate an insane asylum where a former Starfleet captain is being held, only to discover that he has freed the inmates and is running the place.
Kirk beams down on a diplomatic mission... and finds himself in an Enterprise where all the crew have vanished and only a mysterious woman resides.
The Enterprise must deal with discorporeal cloud-like corporeal 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 must resolve a mining dispute on a the cloud city of Stratos to acquire the resources to cure a space plague.
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.
Kirk and Spock meet Abraham Lincoln and Surak of Vulcan and must do battle with some of histories most terrible villians.
Kirk, Spock, and McCoy become trapped in the past of another world.
The Enterprise is in danger when Janice Lester, one of Kirk's former lovers, steals his body.
