THE CAGE
While investigating a distress call from Talos IV, Captain Christopher Pike of the starship Enterprise is captured and tested by Talosians, beings who can project powerfully realistic illusions.

WHERE NO MAN HAS GONE BEFORE
After the Enterprise attempts to cross the Great Barrier at the edge of the galaxy, crew members Gary Mitchell and Elizabeth Dehner develop "godlike" psychic powers which threaten the safety of the crew.

THE MAN TRAP
The Enterprise visits planet 113 for a routine medical inspection of the husband-wife archaeological team stationed there, but find that the wife has been replaced by a deadly, shape-shifting creature.

CHARLIE X
While traveling aboard the Enterprise, a dangerous young man named Charlie Evans terrorizes the crew with his unusual mental powers

WHERE NO MAN HAS GONE BEFORE
After the Enterprise attempts to cross the Great Barrier at the edge of the galaxy, crew members Gary Mitchell and Elizabeth Dehner develop "godlike" psychic powers which threaten the safety of the crew.

THE NAKED TIME
A strange, intoxicating infection, which lowers the crew's emotional inhibitions, spreads throughout the Enterprise. A crew member's inebriated actions place the ship in danger, forcing Scotty to perform a hazardous and untested engineering procedure to save the ship from destruction.

THE ENEMY WITHIN
While beaming up from planet Alpha 177, a transporter accident splits Captain Kirk into two beings: one "good," who acts weak and indecisive; and one "evil", who acts overly aggressive and domineering. Scotty must quickly repair the transporter system to reunite the two Kirks, and to rescue the landing party trapped on the surface of the icy planet below.

MUDD'S WOMEN
The Enterprise encounters interstellar con man Harry Mudd, who is arrested on outstanding charges while ferrying three extraordinarily beautiful women to a remote planet, destined to be wives for the miners located there. In actuality, the plain-looking women use illegal Venus drugs, which make them appear to be much more attractive than their natural appearance; after the drugs wear off, revealing Mudd's deception.

WHAT ARE LITTLE GIRLS MADE OF?
In search of Nurse Chapel's fiancé, renowned exobiologist Roger Korby, the Enterprise visits the icy planet Exo III, where Korby has discovered an ancient machine which allows him to duplicate any living person with an android replacement. Korby plans to use the machine to spread controlled androids throughout the Federation, and replaces Captain Kirk with such a duplicate in an effort to take over the Enterprise.

MIRI
After discovering what appears to be a duplicate of the planet Earth, Captain Kirk and his landing party find a population ravaged by a strange disease, which only children appear to have survived.

DAGGER OF THE MIND
While on a re-supply mission to a rehabilitation colony for the criminally insane, the Enterprise crew discover that the inmates have taken over the asylum and kidnapped Kirk and his companion. Spock performs a mind-meld for the first time in this episode.

THE CORBOMITE MANEUVER
The Enterprise is menaced by a gigantic alien ship whose commander condemns the crew to death. The alien ship appears all-powerful and the alien commander refuses all attempts at negotiation, forcing Kirk to employ an unorthodox strategy to save the ship.

THE MENAGERIE, PART I
Spock hijacks the Enterprise to take his crippled former captain, Christopher Pike, to the forbidden world of Talos IV. He then demands a court martial where he uses the events of "The Cage" to tell the tale of Pike's captivity on the planet years earlier.

THE MENAGERIE, PART II
Spock continues detailing the events of "The Cage" to the tribunal. After witnessing the Talosians' capabilities of mental illusion, Kirk realizes that Spock intends to return Pike to the planet to live a life of illusion, unencumbered by his crippled condition.

THE CONSCIENCE OF THE KING
While visiting an old friend, Kirk learns of suspicions that a Shakespearean actor may actually be the murderous former governor of the planet where Kirk grew up. Kirk invites the acting troupe aboard the Enterprise in order to investigate. But soon, assassination attempts are made on Kirk and another crewman who was an eyewitness to the murders.

BALANCE OF TERROR
While investigating a series of destroyed outposts, the Enterprise discovers a lone Romulan vessel with a cloaking device. The Romulans, having never been seen by humans, are revealed to visually resemble Vulcans, casting doubt on Mr. Spock's loyalty as the two ships become locked in a cat-and-mouse battle through space.

SHORE LEAVE
Captain Kirk orders shore leave for the Enterprise crew on a seemily unihabited planet in the Omicron Delta system. The landing parties begin to see strange sights, such as the White Rabbit, Don Juan, and a sword-wielding samurai. Kirk sees (and fights) an image of Finnegan, a rival from his Starfleet Academy days. Spock discovers that the planet seems to be drawing a large amount of energy from the ship's engines, placing the Enterprise in danger.

THE GALILEO SEVEN
Spock and a scientific party are sent to study the Murasaki 312 quasar aboard the shuttle Galileo. During the survey, the Galileo is forced to make an emergency landing on the planet Taurus II, where the crew fight the planet's dangerous inhabitants. As the crew begin to make repairs, Scotty determines that the shuttle does not have enough fuel to reach orbit carrying all seven passengers, and Spock must contemplate leaving some of his fellow crew behind.

THE SQUIRE OF GOTHOS
The Enterprise discovers a rogue planet drifting through space, inhabited by an eccentric being named Trelane who uses his apparently unlimited power over matter and form to manipulate the crew.

ARENA
The Enterprise comes under attack by unknown aliens while investigating the near-destruction of the Cestus III colony. While chasing the aliens into unexplored space, both ships are captured by the powerful Metrons, who force Kirk and the alien captain (later identified as a member of the Gorn race) to trial by combat: the winner's vessel will be set free, while the loser's ship will be destroyed.

TOMORROW IS YESTERDAY
After accidentally traveling back in time to 1969, the Enterprise rescues USAF Captain John Christopher from his crippled fighter jet. The crew struggles to return to their own time, while simultaneously returning Christopher to the Air Force, removing his knowledge of the future, and all record of contact with the Enterprise.

COURT MARTIALS
Captain Kirk is placed on trial for negligence after a crewman is killed during a severe ion storm. Kirk maintains that his actions were proper and should not have led to the officer's death, but the evidence is strongly against him. All seems lost until new evidence prompts Kirk's attorney to use an innovative defense strategy.

THE RETURN OF THE ARCHONS
The Enterprise discovers a planetary population controlled by a powerful being called Landru. While investigating, Captain Kirk and his landing party are taken captive and discover that the Enterprise crew will be the next to be "absorbed" into Landru's control.

SPACE SEED
The Enterprise discovers an ancient sleeper ship, the SS Botany Bay, which escaped from Earth's Eugenics Wars in the late 20th century. The genetically engineered passengers, led by war criminal Khan Noonien Singh, seize control of the Enterprise and attempt to destroy the ship.

A TASTE OF ARMAGEDDON
On Eminiar VII, the Enterprise finds a civilization at war with its planetary neighbor. Unable to discern any signs of battle from orbit, Captain Kirk leads a landing party to the surface where he discovers the entire war is fought by computer. Even though the war is simulated, citizens who are listed as virtual casualties still report to termination booths to be killed for real. After the Enterprise is destroyed in an attack simulation, Kirk must fight to keep his crew from death.

THIS SIDE OF PARADISE
Despite exposure to deadly radiation, the Federation colony on Omicron Ceti III appears to be thriving. A landing party from the Enterprise investigates, finding the colony's population to be healthy beyond explanation. Leila Kalomi, an old friend of Mr. Spock, shows the landing party strange flowers that seem to impose a state of pure bliss on all exposed to its spores (even Spock). The spores effects spread rapidly throughout the Enterprise, causing the crew to mutiny against Captain Kirk.

THE DEVIL IN THE DARK
Dispatched to the mining colony on Janus VI, the Enterprise is tasked to investigate rumors of a strange, subterranean creature responsible for destruction of equipment and the deaths of fifty miners. Kirk and Spock discover a silicon-based life form, a Horta, which lives in the surrounding rock. After wounding the creature, Spock performs a mind meld, discovering the reason behind the Horta's attacks.

ERRAND OF MERCY
Peace negotiations have collapsed between the Federation and the warlike Klingon Empire. The Enterprise is ordered to protect Organia, a peaceful planet located near the Klingon border. Kirk and Spock beam to the surface to warn the Organians about the Klingons, but soon a Klingon fleet arrives, forcing the Enterprise to abandon the duo on the planet. The natives protect Kirk and Spock, even as Kor, the new Klingon governor, orders mass executions of the Organian people. As both Federation and Klingon fleets converge above the planet, Kirk and Spock execute a daring raid on the Klingon headquarters in an effort to destabilize their control over the planet.

THE ALTERNATIVE FACTOR
While orbiting an apparently dead planet, the Enterprise seems to experience a strange moment of "nonexistence." Captain Kirk discovers a man named Lazarus on the planet below, who claims the effect was caused by his "enemy," later revealed to be an insane version of Lazarus from an alternate dimension. The sane version of Lazarus asks for Kirk's help in defeating his counterpart.

THE CITY ON THE EDGE OF FOREVER
After accidentally overdosing on a powerful stimulant, Dr. McCoy acts erratically and disappears through the Guardian of Forever, a newly-discovered time portal on a remote planet. Kirk and Spock follow after learning that McCoy somehow changed history. Arriving in the 1930s, the duo meet Edith Keeler, a New York social worker who gives them a place to stay. As the days pass, and McCoy is nowhere to be seen, Kirk finds himself falling in love with Keeler... but Spock discovers that Keeler must die to restore the timeline.

OPERATION: ANNIHILATE!
The Enterprise arrives at Deneva - the home of Captain Kirk's brother, Sam - and discovers that the entire planet has been infested with large, amoeba-like aliens that have attacked and killed much of the human population. One of these aliens attaches itself to Spock, who volunteers to become a subject in Dr. McCoy's medical tests. After McCoy accidentally blinds Spock during one of his test procedures, the doctor must quickly find a way to neutralize the dangerous creatures.

AMOK TIME
Suffering through the pon farr, the Vulcan biological mating urge, Spock must return to Vulcan to marry his betrothed or he will die. However, when the Enterprise arrives at Vulcan, complications at the ceremony may endanger Captain Kirk as well.

WHO MOURNS FOR ADONAIS?
The Enterprise is held captive within an energy field which is controlled by an alien who claims to be the Greek god Apollo. Apollo commands Kirk to meet him on the planet's surface. Bones, Chekov, Scotty, and Lieutenant Carolyn Palamis accompany Kirk. Apollo demands the crew worship him as a god at his temple, captivating Carolyn and attacking Scotty when he disobeys. Spock finds a way to get through the energy field and helps Kirk to take down the temple that was the power source of the energy field.

THE CHANGELING
Nomad, a powerful reconstructed artificially intelligent Earth probe with a murderously twisted imperative comes on to the Enterprise and confuses Capt. Kirk as his creator.

MIRROR, MIRROR
Beamed up during an ion storm, which causes a transporter malfunction, the landing party of Kirk, McCoy, Scotty and Uhura find themselves in a mirror universe aboard a parallel Enterprise run by ruthless barbarians. The ion storm also caused their malicious counterparts to beam to the real starship. Kirk and the others must find a way home before they are discovered and exposed by their parallel crew members, who use treachery, back-stabbing and seduction to get what they want.

THE APPLE
Kirk and a landing party beam down to what seems to be an ideal, Eden-like planet. They soon find however that the planet is ruled by a powerful computer that keeps its local inhabitants - primitive and simple tribesmen - happy and healthy. With the Enterprise locked in a tractor beam and slowly being dragged into the planet's atmosphere, Kirk and Spock must find a way to disable to computer. Realizing the threat to its existence, the computer orders the tribesmen to kill the visitors.

THE DOOMSDAY MACHINE
The USS Enterprise encounters the wrecked USS Constellation and its distraught captain determined to stop the giant planet destroying robot ship that killed his crew.

CATSPAW
When Kirk and his landing party arrive on the planet below, they are met by eerie mists, a dark castle, witches, goblins and a black cat. They soon learn that they are under the influence of a wizard, Korob, who tries to bend them to his will. They also soon learn that the black cat they saw is more than she appears and is in fact a powerful witch in her right. It is left to Kirk and Spock to find a means to escape their grasp.

I, MUDD
Harry Mudd returns with a plot to take over the Enterprise by stranding the crew on a planet populated by androids under his command.

METAMORPHOSIS
The Enterprise, carrying a critically ill Federation Ambassador Nancy Hedford, encounter a mysterious energy cloud which pulls them down to planet Gamma Canaris N, where they meet a castaway. This young man purports to be Zefram Cochrane, the inventor of the Warp Drive over 100 years ago. But in history he had lived to be 80 years of age before disappearing somewhere in space. Apparently the same energy cloud which brought the Enterprise to the planet also rejuvenated Cochrane, making him effectively immortal. Can Kirk get the Enterprise released on time to get the ambassador the medical help she needs, or is there something else in this situation which might be a solution?

JOURNEY TO BABEL
The Enterprise hosts a number of quarrelling diplomats, including Spock's father, but someone on board has murder in mind.

FRIDAY'S CHILD
The Federation is in competition with the Klingons for an alliance with the inhabitants of Capella IV. The Capellans are a warrior tribe and there is dissension among them as to who to sign the mining rights treaty with. McCoy is familiar with their customs having once spent several months there. When a Capellan, who clearly favors the Klingons, stages a coup, Kirk, Spock and McCoy flee with the now dead leader's wife, who is about to give birth. Meanwhile, the Enterprise receives a distress call from a Federation vessel under attack and, with Scotty in command, leaves orbit.

THE DEADLY YEARS
A landing party from the Enterprise is exposed to strange form of radiation which rapidly ages them.

OBSESSION
Capt. Kirk obsessively hunts for a mysterious cloud creature he encountered in his youth.

WOLF IN THE FOLD
Kirk and the Enterprise Computer become detectives after Scotty is accused of murdering women on a pleasure planet.

THE TROUBLE WITH TRIBBLES
To protect a space station with a vital grain shipment, Kirk must deal with Federation bureaucrats, a Klingon battle cruiser and a peddler who sells furry, purring, hungry little creatures as pets.

THE GAMESTERS OF TRISKELION
Kirk, Uhura and Chekhov are trapped on a planet where gladiators are enslaved and trained to perform for the amusement of bored, faceless aliens.

A PIECE OF THE ACTION
The Enterprise is investigating a planet visited 100 years ago by the USS Horizon. Kirk, Spock, and McCoy beam down and find themselves in a culture similar to Earth gangs of the 1920's. They are quickly taken prisoner by men in the employ of a mob boss named Bela Oxmyx. He wishes them to give him phasers in exchange for "a piece of the action", and when they refuse Oxmyx puts them under guard. Kirk creates a diversion with a card game called "fizzbin". Without their equipment, the trio must find a way to unite the planet and escape to the Enterprise.

THE IMMUNITY SYNDROME
The Enterprise encounters a gigantic energy draining space organism that threatens the galaxy.

A PRIVATE LITTLE WAR
Kirk returns to the planet Neural which he had spent time 13 years before. A friend of his from his previous visit is now leader of his people. While trying to uphold the Federation's prime directive, the Klingons are providing more advanced technology to their enemies.

RETURN TO TOMORROW
The last three members of an ancient race far more advanced than humans, who survive only as disembodied thought, wish to borrow the bodies of Kirk, Spock and Dr. Mulhall.

PATTERNS OF FORCE
Looking for a missing Federation cultural observer, Kirk and Spock find themselves in a planet whose culture is now modeled on the German Nazi Party of old Earth in the 1930's.

BY ANY OTHER NAME
Galactic alien scouts capture the Enterprise for a return voyage and a prelude to invasion. Kirk's one advantage - they're not used to their adopted human form.

THE OMEGA GLORY
Responding to a distress signal, Kirk finds Captain Tracey of the USS Exeter violating the prime directive and interfering with a war between the Yangs and the Kohms to find the secret of their longevity.

THE ULTIMATE COMPUTER
Kirk and a sub-skeleton crew are ordered to test out an advanced artificially intelligent control system that could potentially render them all redundant.

BREAD AND CIRCUSES
While searching for the crew of a destroyed spaceship, the Enterprise discovers a planet whose oppressive government is a 20th-century version of Earth's Roman empire. Kirk, Spock, and McCoy meet the rebels, seemingly sun worshipers, but are quickly kidnapped by the regime. The missing Captain Merrick is revealed as the "First Citizen" and pawn of the regime, but he and the rebels ultimately help Kirk and company to escape. Back on the Enterprise, Uhura observes that the crew's understanding that the rebels are sun worshipers was not completely accurate.

ASSIGNMENT: EARTH
The Enterprise travels back in time to 1968, where the crew encounters the mysterious Gary Seven who claims to be sent by advanced beings trying to help Earth.

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

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

THE PARADISE SYNDROME
Trapped on a planet whose inhabitants resemble the Northwestern American Indians 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.

AND THE CHILDREN SHALL LEAD
The Enterprise reaches a Federation colony where the adults have all killed each other but the children play without care.

IS THERE IN TRUTH NO BEAUTY?
Telepath Miranda escorts an alien ambassador so hideously ugly that the sight of him can drive a Human insane.

SPECTRE OF THE GUN
As punishment for trespassing on their planet, the inhabitants condemn Capt. Kirk and his landing party as the losing side of a surreal recreation of the Gunfight at the OK corral.

DAY OF THE DOVE
An entity traps the Enterprise crew and the crew of a disabled Klingon battle cruiser in an unending war aboard the Enterprise.

FOR THE WORLD IS HOLLOW AND I HAVE TOUCHED THE SKY
The Enterprise discovers an apparent asteroid that is on a collision course with a planet is actually an ancient populated generation ship.

THE THOLIAN WEB
Kirk and the derelict starship Defiant vanish into a spatial interphase between universes. To rescue him, Spock must maintain position despite a growing, violent hysteria aboard the Enterprise like that which destroyed the Defiant's crew, as well as a force field being laid around the Enterprise by Tholian patrol ships.

PLATO'S STEPCHILDREN
On an urgent medical emergency Kirk, Spock and McCoy encounter an alien society who had once flourished on earth during the time of Plato. Since reaching their current planet they had developed psychokinetic powers while also losing the ability for their bodies to combat even the simplest infections. When Doctor McCoy refuses their offer to stay, they begin make sport with Kirk, McCoy, Nurse Chapel and Lieutenant Uhura using their psychokinetic powers.

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

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

ELAAN OF TROYIUS
The Enterprise transports Elaan, a member of the ruling dynasty of the warrior Elasians, to the planet of their enemy, the Troyians, so that her arranged marriage will halt their interplanetary war. Kirk must teach the arrogant, vicious princess the ways of polite society but falls victim to the legendary weapon of Elasian women: their tears act as a love potion. Spock tracks what may be another ship shadowing the Enterprise and Kirk, distracted by Elaan, must fight against other parties interested in preventing the Federation's peace efforts.

WHOM GODS DESTROY
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.

LET THAT BE YOUR LAST BATTLEFIELD
The Enterprise encounters two duo-chromatic and mutually belligerent aliens who put the ship in the middle of their old conflict.

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

THAT WHICH SURVIVES
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.

THE LIGHTS OF ZETAR
The Enterprise is on course to install new equipment on Memory Alpha, the central library storage facility for the Federation. Chief Engineer Scott has been working closely on the project with Lieutenant Mira Romaine with whom he has been forming a romantic attachment. The Enterprise encounters a space storm that kills the staff at Memory Alpha and possesses Lieutenant Mira Romaine.

REQUIEM FOR METHUSELAH
When Kirk, Spock and McCoy beam down to a supposed uninhabited planet to gather the mineral ryetalyn to fight a plague of Rigelian fever on-board the Enterprise, they find a fellow earth-man called Flint and his extremely intelligent female ward Rayna who Kirk begins to fall in love with. Flint then proceeds to trap them on his planet and takeover the Enterprise.

THE WAY TO EDEN
The Enterprise picks up a group of renegades who have rejected modern technological life to search for the mythical planet Eden.

THE CLOUD MINDERS
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.

THE SAVAGE CURTAIN
Kirk, Spock, Abraham Lincoln, and Surak are pitted in battle against four notorious villains from history for the purpose of helping a molten rock creature's understanding of a concept he does not understand, 'good verses evil'.

ALL OUR YESTERDAYS
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.

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