The Enterprise finds an ancient abandoned starship with a malevolent entity aboard, eager to take over the Starfleet ship.

After finding himself erased from recent history, Spock must travel back in time to save himself as a youth.

The crew of the Enterprise must stop a living planet-consuming cloud before it attacks an inhabited world.

Female crew members must take over the Enterprise when the men are incapacitated by a race of sirens.

Cyrano Jones returns, infesting the Enterprise with tribbles that now grow to monstrous size.

A famous humanitarian is found alive near the Romulan Neutral Zone after being missing for five years, but he may not be who he claims to be.

On a planet of intelligent plantlike creatures, the clone of a human scientist clones Mr. Spock for use in a galactic peace mission.

At the centre of the galaxy, a race puts the Enterprise crew on trial for past grievances.

Upon returning to the amusement park planet, the Enterprise crew finds the computer, which generates the planet's sophisticated robots, running amok, with the caretaker nowhere to be found.

The Enterprise crew once again runs afoul of the incorrigible Harry Mudd, this time hawking a love potion that greatly influences Spock and the crew.

Exposed to spiroid epsilon waves, the Enterprise crew begins to shrink in size. If a way can not be found to stop their condition, they will soon be too small to control the ship.

The Enterprise and a Klingon ship are trapped in space-time warp where only their cooperation will allow them to escape.

While the Enterprise investigates a water-world, Captain Kirk and Commander Spock go missing. They've been abducted by the world's inhabitants and altered into water-breathers as well.

Spock, Uhura and Sulu discover an ancient multi-use weapon and are captured by the Kzinti who are equally interested in it.

While investigating the disappearance of Federation members, Kirk and his landing party find themselves placed in an alien zoo.

A team comprising various experts (Kirk and Spock among them) must recover an artifact known as the Soul of the Skorr. The theft must be kept secret or a galactic holy war could break out.