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.

While exploring the edge of the galaxy, the Enterprise encounters an energy barrier that gives some crewmen strange powers.

A strange alien substance causes the crew to lose their inhibitions.

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.

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.

The Enterprise encounters a vast alien ship that threatens the Enterprise with destruction.

Kirk is one of the last survivors who can identify a mass killer, who lurks among a Shakespearean troupe aboard the Enterprise.

The Enterprise finds itself at the mercy of a seemingly omnipotent being who fancies himself an 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.

The Enterprise encounters a seemingly peaceful civilization run by a "benevolent" being named Landru... who intends for them to join his people.

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 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 crew try to rescue colonists from deadly radiation, but instead encounter strange alien spores that seem to offer paradise.

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 encounter an alien named Lazarus who claims to be from an anti-matter universe.

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 threatening the lives of millions.

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

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

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

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.

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

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.

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

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

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

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

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

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

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

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

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.

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

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.

Captain Kirk must find the cure to a deadly disease and put an end to another Starfleet captain's cultural interference.

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

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