An alien female beams aboard the ship and, after incapacitating the rest of the crew, surgically removes Spock's brain. Kirk and the crew have just hours to locate and replace it before Spock's body dies.

The crew of the Enterprise are on a secret mission to steal a Romulan cloaking device.

An alien device on a primitive planet erases Captain Kirk's memory, and he begins a new life with the planet's indigenous people.

On a distant planet, Kirk, Spock and McCoy find a scientific team dead, and their children who, unknown to the crew, have great powers at their disposal.

The Enterprise travels with an alien ambassador whose appearance induces madness.

Having been found trespassers into Melkotian space, Captain Kirk and his companions are sent to die in a re-enactment of the gunfight at the O.K. Corral.

An alien force drives the crew of the Enterprise into brutal conflict with the Klingons.

The crew of the Enterprise rush to stop an asteroid from colliding with a Federation world, but discover the asteroid is actually an inhabited generation ship.

Captain Kirk is caught between dimensions while the crew of the Enterprise works to retrieve him. All the while, the Tholians demand that the Enterprise leave their space.

The crew of the Enterprise encounters an ageless and sadistic race of humanoids with the power of telekinesis and who claim to have organized their society around Ancient Greek ideals.

Invisible "time-accelerated" aliens take over the Enterprise and attempt to abduct the crew for use as "genetic stock".

While visiting a doomed planet, the landing party is subject to torturous experiments by powerful aliens.

The USS Enterprise ferries a spoiled princess whose betrothal to a royal Troyian is hoped will bring peace to a star system at war.

The Enterprise encounters two duo-chromatic and mutually belligerent aliens who put the ship in the middle of their old conflict.

A race of overpopulated aliens abduct Captain Kirk to solve their problem.

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.

Strange incorporeal aliens threaten the Memory Alpha station and the Enterprise.

The crew of the Enterprise encounter an immortal human in this science fiction variation on Shakespeare's The Tempest.

The Enterprise picks up a group of space "hippies" looking for Eden.

Captain Kirk races against time to acquire plague-fighting minerals from a world in the midst of a civil uprising against a grievous social class disparity.

Aliens force Captain Kirk and First Officer Spock to join forces with "Abraham Lincoln" and "Surak" to battle villains in a contest of good vs. evil.

Kirk, Spock and McCoy are trapped in two parts of another planet's past - a world threatened with destruction when its sun goes supernova.

The Enterprise is in danger when Janice Lester, one of Kirk's former lovers, steals his body.