A transporter mishap swaps Captain Kirk and his companions with their evil counterparts in a parallel universe. In the so-called Mirror Universe, the Enterprise is a ship of the Terran Empire, an organization as evil as the United Federation of Planets is benevolent.

First Officer Spock returns to his home world for a brutal Vulcan mating ritual.

The Enterprise must protect a very important shipment of grain from both Klingons and some adorable creatures called tribbles.

The starship Enterprise and its heavily-damaged sister ship, the USS Constellation, must work together to stop an alien planet-killing machine headed for the heart of Federation territory.

The Enterprise must transport dignitaries to a peace conference, with an assassin on the loose.

A skeleton Enterprise crew are assigned to test a revolutionary computer system that is given total control of the ship.

The crew of the USS Enterprise deals with an indestructible planet-destroying space probe.

The crew of the Enterprise tracks down a Federation observer on a planet dominated by a "Naziesque" regime.

Beings from another galaxy commandeer the Enterprise in an attempt to return home.

Strange radiation exposes the command crew of the Enterprise to the effects of rapid aging.

The crew of the Enterprise encounters an energy-draining field which may be able to destroy the galaxy.

The Enterprise visits a planet with an Earth-like 1920s gangster culture.

Ancient alien minds are given control of Captain Kirk's and First Officer Spock's bodies.

Captain Kirk has a second run-in with the conman, Harry Mudd. Mudd is now the supreme ruler of a planet of androids who cater to his every whim.

While back in time observing Earth in 1968, the Enterprise crew encounters the mysterious Gary Seven who has his own agenda on the planet.

A shuttle crew from the USS Enterprise encounters a man out of history and his mysterious alien companion.

Captain Kirk and his companions are abducted into slavery and trained to fight as gladiators for the gambling entertainment of three disembodied beings.

Captain James T. Kirk becomes obsessed with destroying a deadly entity he once encountered in his youth.

A series of bizarre murders points to Mr. Scott as the prime suspect.

The crew of the Enterprise discovers Klingon interference in the development of a formerly peaceful planet and is forced to help maintain a balance of power.

The Enterprise crew investigates the disappearance of a ship's crew on a planet that is a modern version of the Roman Empire.

The crew of the Enterprise visits a mysterious paradisical planet controlled by a computer that is served by the local inhabitants.

The crew of the Enterprise become entangled in a planet's tribal power struggle.

The crew of the Enterprise are held captive by an alien who turns out to be the Greek god Apollo.

Two powerful aliens threaten the well-being of the Enterprise and her crew.