Captain Pike is captured by the illusion-creating Talosians, who want Pike as a prize specimen for their zoo.
An energy barrier at the edge of the galaxy mutates Kirk's friend , Gary Mitchel, into godlike being.
A powerful captures the Enterprise, but it is just a test to learn the Federation's intentions.
The Enterprise rescues con man Harry Mudd and his "cargo" of three beautiful women.
A transport malfunction splits Kirk in to two people, each with half of his personality.
A salt creature that can disguise itself in any form stalks the Enterprise.
A mysterious alien virus strips the Enterprise crew of the inhibitions, exposing their innermost thoughts.
An adolescent human boy, raised among aliens who have given him supernatural powers, finds it impossible to return to normal human society.
Kirk matches wits with the commander of an invisible Romulan spaceship.
Nurse Chapple's missing fiancé is found living in a "perfect" android body.
The Enterprise investigates a revolutionary treatment for the criminally insane, but the new device kills with loneliness.
The Enterprise discovers a planet where all the adults have dies, leaving behind a population of nearly immortal children.
Kirk suspects a distinguished Shakespearean actor may have been an infamous mass murderer many years ago.
A shuttlecraft piloted by Spock crashes on Taurus 2, forcing him to grope with the life-and-death responsibilities of command.
Kirk's Career is jeopardized when he is put on trial for apparently causing the death of an Enterprise crew member.
Spock hijacks the Enterprise to return Captain Pike to Talos 4.
The Enterprise crew is baffled by a mysterious planet on which dreams come true.
An incredibly powerful alien life-form torments the Enterprise crew, but is found out to be simply a small child playing with his toys.
A powerful race known as the Metrons put Kirk and a Gorn captain on a planetoid where they are expected to resolve their differences by fighting to death.
A mysterious "rip" in space is opened between our universe and an antimatter universe, threatening the existence of both.
The Enterprise accidentally travels back into time to the 20th century, where it is sighted by the Air Force as a UFO.
The Enterprise, investigating the disappearance of the starship Anchon, finds a planet ruled by a computer named Landru.
The Enterprise is caught in a bizarre interplanetary war fought entirely by computers, but with real deaths.
The Enterprise is commandeered by the 20th Century superhuman Khan Singh, who has survived for centuries in cryogenic sleep aboard the SS Botany Bay.
Mr. Spock finds happiness at a colony where alien spores provide total contentment.
A terrifying subterranean creature is found to be a simply a mother protecting her eggs.
The Enterprise tries to protect Organia, an apparently primitive planet, from the Klingons, but the Organians neither want or need assistance.
McCoy, suffering from an accidental drug overdose, flees through a time portal into Earth of the 1930's, where he causes serious damage to the flow of history.
Kirk finds his brother and sister-in-law are victims of neural parasites causing planetwide insanity.
