The crew of the Enterprise pursues a mysterious woman who has abducted Spock's brain.

An apparently insane Capt. Kirk has the Enterprise deliberately enter the Romulan Neutral Zone where the ship is immediately captured by the enemy.

Trapped on a planet whose inhabitants are descended from Northwestern Native Americans, Kirk loses his memory and is proclaimed a God while the crippled Enterprise races back to the planet before it is destroyed by an asteroid.

The Enterprise reaches a Federation colony where the adults have all killed themselves but the children play without care.

Lovely telepath Miranda is aide to Ambassador Kollos, in a box to stop insanity when humans see Medusans. She rejects Larry, a designer of Enterprise, and senses murderous intent nearby.

As punishment for ignoring their warning and trespassing on their planet, the Melkot condemn Capt. Kirk and his landing party to the losing side of a surreal recreation of the 1881 historic gunfight at the OK Corral.

Both humans and Klingons have been lured to a planet by a formless entity that feeds on hatred and has set about to fashion them into a permanent food supply for itself.

The Enterprise discovers an apparent asteroid that is on a collision course with a planet is actually an ancient populated generation ship.

With Capt. Kirk and the derelict USS Defiant apparently lost, the Enterprise grapples with an insanity causing plague and an attack by the Tholians.

After Dr. McCoy helps the leader of a planet populated by people with powerful psionic abilities, they decide to force him to stay by torturing his comrades until he submits.

A group of aliens who exist in a state of incredible acceleration invade the Enterprise and abduct Capt. Kirk.

Trapped in an alien laboratory, Kirk, Spock and McCoy meet an empath and are involved in a series of experiments.

While transporting an arrogant, demanding princess for a political marriage, Captain Kirk must cope both with her biochemical ability to force him to love her, as well as sabotage on his ship.

Kirk and Spock are taken prisoners by a former starship captain named Garth, who now resides at, and has taken over, a high security asylum for the criminally insane.

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

Kirk beams down to the planet Gideon and appears to find himself trapped on a deserted Enterprise. Spock on the real Enterprise must use his diplomatic skills to deal with the uncooperative inhabitants of Gideon and find the Captain.

After the Enterprise landing party beams down to investigate a geologically interesting planet, their ship is hurled across the galaxy. Kirk and company find a deserted outpost guarded by the deadly image of a beautiful woman.

A mysterious, twinkling mass of sapient energy ravages an important archive and Scotty's new girlfriend may be linked to it.

On a planet, looking for an urgent medicinal cure, Kirk, Spock and McCoy come across a dignified recluse living privately but in splendor with his sheltered ward and a very protective robot servant.

A group of idealistic hippies, led by an irrational leader, come aboard the U.S.S. Enterprise.

Kirk and Spock are caught up in a revolution on a planet where intellectuals and artists live on a utopian city in the sky while the rest of the population toils in mines on the barren surface below.

Kirk, Spock, Abraham Lincoln and Vulcan legend Surak are pitted in battle against notorious villains from history for the purpose of helping a conscious rock creature's understanding of a concept he does not understand, "good vs. ...

When Kirk, Spock and McCoy investigate the disappearance of a doomed planet's population, they find themselves trapped in different periods of that world's past.

Captain Kirk's insane ex-lover Dr. Janice Lester forcibly switches bodies with him in order to take command of the Enterprise.