Star Trek The Original Series Episode Guide

Star Trek TOS Episode Guide


Leonard Nimoy, William Shatner, and Joan Collins in "The City on the Edge of Forever" episode of Star Trek (1966).

The Original “Star Trek” Episode Guide

First Season | Second Season | Third Season

contributed by Lou Israel; proofread and edited by Suzanne


  • (THE) MAN TRAP—A shape-changing salt monster kills crewmen at random.
  • CHARLIE X—A young orphaned boy is brought aboard the Enterprise and soon wreaks havoc with his powers.
  • WHERE NO MAN HAS GONE BEFORE—The Enterprise goes to the galaxy’s edge, where two of the crew develop godlike powers.
  • (THE) NAKED TIME—A virus on the ship releases the crew’s inhibitions and innermost feelings at the worst possible time.
  • (THE) ENEMY WITHIN—A transporter accident splits Kirk into two beings: one good, one evil.
  • MUDD’S WOMEN—The first Harry Mudd episode, where he brings three women on board as “wives” for three miners.
  • WHAT ARE LITTLE GIRLS MADE OF?– Nurse Chapel’s former fiancé is now the leader of a group of androids.
  • MIRI—-A group of very old children will die of a horrible disease as they enter puberty.
  • DAGGER OF THE MIN–The director of a penal colony has a machine that molds the inmates’ minds to only obey him.
  • (THE) CORBOMITE MANEUVER—-The Enterprise contacts an alien life form that decides to sentence them to death.
  • (THE) MENAGERIE—Spock kidnaps the ship’s former captain and takes him to a planet that has been forbidden by Starfleet and may lead to the death penalty.
  • (THE) CONSCIENCE OF THE KING—Kirk suspects an actor to be the same man who butchered a human colony many years ago.
  • BALANCE OF TERROR—The first encounter with the Romulans in over a century leads to a tense situation.
  • SHORE LEAVE— The crew visits a beautiful planet for vacation, only to find that their thoughts can have dire consequences.
  • (THE) GALILEO SEVEN—Spock and 6 others are forced to crash-land on an unfriendly planet and fight for their lives.
  • (THE) SQUIRE OF GOTHOS—The Enterprise meets up with a very powerful being who just wants them to play with him.
  • ARENA—After pursuing an alien ship, Kirk is transported down to a planet where he must kill the alien captain to survive.
  • TOMORROW IS YESTERDAY—The Enterprise accidentally is thrown back to 1960’s Earth, where the crew must be careful not to change history.
  • COURT-MARTIAL—-Kirk stands trial for the death of a crewman—and he must prove his innocence.
  • (THE) RETURN OF THE ARCHONS—The Enterprise discovers a planet where the peaceful inhabitants worship a computer, which allows them one night of violence per year.
  • SPACE SEED—The first appearance of Khan, a 20th century man prepared to lead his genetically-enhanced people to take over the Enterprise and then the universe.
  • (A)TASTE OF ARMAGEDDON—On a planet where war is fought by computers, Kirk and crew must show the people the errors of their ways.
  • THIS SIDE OF PARADISE—On a planet where everyone should be dead, the crew discover some interesting surprises, and Spock falls in love for the first time.
  • (THE) DEVIL IN THE DARK—On a mining planet where men die at the hands of a creature who eats rock, the Enterprise is sent to make things right.
  • ERRAND OF MERCY—On a planet of “sheep”, Kirk comes face to face with the wolves: the Klingons.
  • (THE) ALTERNATIVE FACTOR—Time-displacements and doubles abound as the Enterprise battles a time-traveling humanoid.
  • (THE) CITY ON THE EDGE OF FOREVER—McCoy goes back in time and accidentally changes Earth’s history; Kirk & Spock must restore it.
  • OPERATION: ANNIHILATE!–“Things” attack, and control the minds of colonists on a planet, including Kirk’s brother’s family.

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  • AMOK TIME–Spock must get to Vulcan and choose a wife – or die.
  • WHO MOURNS FOR ADONAIS?–The crew meets up with a “god” from ancient Greece who demands they worship him.
  • (THE) CHANGELING—-A 20th century machine meets up with Captain Kirk; its purpose—destroy all life-forms.
  • MIRROR, MIRROR—Kirk and three other crewmates are transported into a savage, parallel universe.
  • (THE) APPLE—A peaceful people worship a machine as their “god”; Kirk battles it (and them) to save his ship.
  • (THE) DOOMSDAY MACHINE—The Enterprise must help another starship captain defeat a robotic planet-killer.
  • CATSPAW—Three crewmen are abducted; Kirk, Spock & McCoy investigate an elaborate trick-or-treat on a Halloween-like planet.
  • I, MUDD—Harry Mudd pops up again, this time on a planet where androids rule – and intend to take over the Enterprise.
  • METAMORPHOSIS—Kirk, Spock, and McCoy find a man who should be long dead,  and an entity that wants to keep them prisoner in order to give the man companionship.
  • JOURNEY TO BABEL—The Enterprise hosts dozens of ambassadors and aliens, including Spock’s parents, on a diplomatic mission.
  • FRIDAY’S CHILD—-The Federation and Klingons vie for the attentions of a people who choose combat over love, and whose leader may turn out to be McCoy’s “child”.
  • (THE) DEADLY YEARS—After returning from a supposedly harmless planet, Kirk and his landing party begin to age very quickly.
  • OBSESSION—A creature that has tortured Kirk’s memory for many years returns with a vengeance, killing at will.
  • WOLF IN THE FOLD–On an R&R planet, Scotty is accused of murder.
  • (THE) TROUBLE WITH TRIBBLES—-Kirk and the Klingons battle it out for control of a planet, peace on a space station, and possession of some tribbles.
  • (THE) GAMESTERS OF TRISKELION—Kirk, Uhura and Chekov find themselves on a planet where they are nothing but slaves, performing to please their masters.
  • (A) PIECE OF THE ACTION—The crew tries to find peace for the citizens of a planet modeled after 1920’s Chicago.
  • (THE) IMMUNITY SYNDROME—The Enterprises has to match wits against a giant amoeba that is about to reproduce.
  • (A) PRIVATE LITTLE WAR—The Enterprise finds itself in an arms race with the Klingons on a formerly peaceful planet.
  • RETURN TO TOMORROW—Mentally powerful beings take over Kirk and Spock’s bodies, but one has a hidden agenda.
  • PATTERNS OF FORCE—A planet patterned after Nazi Germany threatens its peaceful neighbor, as well as  Kirk and Spock.
  • BY ANY OTHER NAME—A handful of aliens who can immobilize humans hijack the Enterprise and take it to another galaxy.
  • (THE) OMEGA GLORY—On a planet where the natives live a very long life, a renegade starship captain may shorten Kirk’s and Spock’s.
  • (THE) ULTIMATE COMPUTER—The computer that may replace starship crews and captains gets its test run aboard the Enterprise.
  • BREAD AND CIRCUSES—-On a planet based on ancient Rome (yet with 20th century technology), Kirk, Spock & McCoy learn the limitations and frustrations of the Prime Directive.
  • ASSIGNMENT: EARTH—As the Enterprise investigates 20th Century Earth, a human being beams aboard, claiming that only he can save it from destruction.

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  • SPOCK’S BRAIN—A beautiful woman steals Spock’s brain; the Enterprise follows her back to her planet, where their civilization is kept going by a computer.
  • (THE) ENTERPRISE INCIDENT—Kirk goes crazy and is captured by Romulans, whose leader tempts Spock to join them.
  • (THE) PARADISE SYNDROME—Kirk gets amnesia on a planet inhabited by descendants of Native Americans, which will be destroyed if he doesn’t recover and remember.
  • AND THE CHILDREN SHALL LEAD—A handful of kids are the only survivors of a massacre that killed their parents, but they act like they don’t care!
  • IS THERE IN TRUTH NO BEAUTY?– While transporting an “ugly” alien ambassador, the Enterprise is the scene for murder, deception, and surprises.
  • SPECTRE OF THE GUN—Because they accidentally trespassed into Melkotian space, Kirk, Spock, Scotty, McCoy and Chekov are sentenced to execution by acting out the Gunfight at the O.K. Corral.
  • DAY OF THE DOVE—The crew is forced to battle Klingons by an entity that feeds off violence.
  • FOR THE WORLD IS HOLLOW AND I HAVE TOUCHED THE SKY—A dying McCoy finds love in the strangest place: on a spaceship disguised as an asteroid.
  • (THE) THOLIAN WEB—Kirk is missing and presumed dead while Spock and the crew fight madness and an alien’s trap.
  • PLATO’S STEPCHILDREN—Sadistic aliens with incredible mental and telekinetic powers try to get McCoy to stay and be their physician by torturing Kirk and Spock.
  • WINK OF AN EYE—Kirk disappears into another reality, where he moves too fast to be seen, along with aliens who try to put the ship into a deep freeze.
  • (THE) EMPATH—While investigating the disappearance of two scientists, Kirk, Spock, and McCoy become unwitting lab rats in an alien race’s test.
  • ELAAN OF TROYIUS—The ship transports a spoiled princess, who’s to be married off in order to stop a star system at war.
  • WHOM GODS DESTROY-A former Starfleet captain, now gone mad, leads a revolt, and the lunatics (literally) take over the asylum.
  • LET THAT BE YOUR LAST BATTLEFIELD—The crew finds two aliens, one white-black, the other black-white, have nothing else in common but their hatred of one another.
  • (THE) MARK OF GIDEON—While attempting to beam down to an overcrowded planet, Kirk rematerializes on board the Enterprise, which appears to be deserted.
  • THAT WHICH SURVIVES—On a supposedly dead planet, Kirk and three others discover the Enterprise has disappeared, and an alien projection is after them!
  • (THE) LIGHTS OF ZETAR—Scotty’s girlfriend is taken over by aliens who do not accept their own deaths.
  • REQUIEM FOR METHUSELAH—The Enterprise becomes a plague ship, and Kirk discovers that the only person with the antidote is a very secretive man with a very long past.
  • (THE) WAY TO EDEN—A group of “space hippies”, including Chekov’s old girlfriend, sabotage the Enterprise in their quest for paradise planet.
  • (THE) CLOUDMINDERS—-An unseen gas is the only thing that keeps two races apart – one on the ground, and one on a city in the clouds.
  • (THE) SAVAGE CURTAIN—Kirk and Spock are matched up against some of history’s worst villains to teach an alien race about good and evil.
  • ALL OUR YESTERDAYS—-Spock and McCoy are separated from Kirk in a planet’s past, where McCoy falls ill, and Spock falls in love.
  • TURNABOUT INTRUDER—Kirk’s old girlfriend switches bodies with him, then tries to murder him and claim the Enterprise for herself.

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From Jeff:

80 – Futurama : Where No Fan Has Gone Before

In a spoof of Star Trek’s “The Menagerie”, Fry meets up with the real life cast of Star Trek The Original Series (Minus McCoy and Scotty).  In this Episode, however , Scotty was replaced by “Welshie”.  There are several TOS References mentioned in this show. This Episode aired during the 4th year of Futurama. It could be considered an Original Series Cast Reunion Episode.

TOS Movies ( by Suzanne)

“Star Trek: The Motion Picture” (1979) Admiral Kirk returns to take command of the retrofitted Enterprise to stop the threat of a destructive cloud heading towards Earth.

“Star Trek II: The Wrath of Khan” (1982) Khan Noonien Singh captures the starship Reliant and uses it to go after Kirk for revenge; once again assuming command of the Enterprise, Kirk must stop Khan from stealing the Genesis device.

“Star Trek III: The Search for Spock” (1984) Kirk learns that Spock put his katra into McCoy before he died, so he retrieves Spock’s body from the Genesis planet. The klingons attack, to get the Genesis device.

“Star Trek IV: The Voyage Home” (1986) The Enterprise crew must journey back in time to save the humpback whales in order to stop a giant probe from destroying the Earth in their own time.

“Star Trek V: The Final Frontier” (1989) Spock’s brother, Sybok, hijacks the new Enterprise-A to find God at the edge of the universe, while the Klingons follow them to seek revenge on Kirk.

“Star Trek VI: The Undiscovered Country” (1991) The Enterprise carries the Klingon Chancellor to an important peace summit; when he’s assassinated, Kirk and McCoy are blamed and sentenced to a Klingon prison planet. Spock tries to figure out who’s behind all of it and rescue them.


Spock (Leonard Nimoy), Kirk (William Shatner), Sulu (George Takei), Leila (Jill Ireland), and Kelowitz (Grant Woods) in "This Side of Paradise" on Star Trek (1967).

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