Amok Time
E1
First Officer Spock returns to his home world for a brutal Vulcan mating ritual.
Who Mourns for Adonais?
E2
The crew of the Enterprise are held captive by an alien who turns out to be the Greek god Apollo.
The Changeling
E3
The crew of the USS Enterprise deals with an indestructible planet-destroying space probe.
Mirror, Mirror
E4
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 Apple
E5
The crew of the Enterprise visits a mysterious paradisical planet controlled by a computer that is served by the local inhabitants.
The Doomsday Machine
E6
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.
Catspaw
E7
Two powerful aliens threaten the well-being of the Enterprise and her crew.
I, Mudd
E8
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.
Metamorphosis
E9
A shuttle crew from the USS Enterprise encounters a man out of history and his mysterious alien companion.
Journey to Babel
E10
The Enterprise must transport dignitaries to a peace conference, with an assassin on the loose.
Friday's Child
E11
The crew of the Enterprise become entangled in a planet's tribal power struggle.
The Deadly Years
E12
Strange radiation exposes the command crew of the Enterprise to the effects of rapid aging.
Obsession
E13
Captain James T. Kirk becomes obsessed with destroying a deadly entity he once encountered in his youth.
Wolf in the Fold
E14
A series of bizarre murders points to Mr. Scott as the prime suspect.
The Trouble With Tribbles
E15
The Enterprise must protect a very important shipment of grain from both Klingons and some adorable creatures called tribbles.
The Gamesters of Triskelion
E16
Captain Kirk and his companions are abducted into slavery and trained to fight as gladiators for the gambling entertainment of three disembodied beings.
A Piece of the Action
E17
The Enterprise visits a planet with an Earth-like 1920s gangster culture.
The Immunity Syndrome
E18
The crew of the Enterprise encounters an energy-draining field which may be able to destroy the galaxy.
A Private Little War
E19
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.
Return to Tomorrow
E20
Ancient alien minds are given control of Captain Kirk's and First Officer Spock's bodies.
Patterns of Force
E21
The crew of the Enterprise tracks down a Federation observer on a planet dominated by a "Naziesque" regime.
By Any Other Name
E22
Beings from another galaxy commandeer the Enterprise in an attempt to return home.
The Omega Glory
E23
Captain Kirk must find the cure to a deadly disease and put an end to another Starfleet captain's cultural interference.
The Ultimate Computer
E24
A skeleton Enterprise crew are assigned to test a revolutionary computer system that is given total control of the ship.
Bread and Circuses
E25
The Enterprise crew investigates the disappearance of a ship's crew on a planet that is a modern version of the Roman Empire.
Assignment: Earth
E26
While back in time observing Earth in 1968, the Enterprise crew encounters the mysterious Gary Seven who has his own agenda on the planet.