Episode: 1x01 | Airdate: Sep 8, 1966
Professor Robert Crater and his wife Nancy are archeologists, investigating the ruins of a civilization on M-113. Enterprise visits for the annual physical examination required by regulations, but the professor seems oddly reluctant. He insists all he and his wife need is salt to cope with the heat. Then Crewman Green dies, his face marked by odd red rings. Crater says he ate the borgia plant which contains toxic chemicals. But its symptoms do not include the red mottling. Kirk and Spock are determined to discover what's going on, and doubly so when a crewman on the ship dies the same way as Green.
Episode: 1x02 | Airdate: Sep 15, 1966
A small ship, the Antares, transfers a passenger to Enterprise. He is Charles Evans, recently recovered from the lifeless planet Thasus, having survived there since he was marooned by the crash that killed his parents. Oddness seems to accompany Charlie. Antares calls, with a warning her captain does not finish delivering before his ship explodes. Soon enough it becomes clear that Charlie is a young man of extraordinary powers, able to cause things to happen merely by willing them to. Kirk must regain control of his ship from a troubled, dangerously powerful teenager.
Episode: 1x03 | Airdate: Sep 22, 1966
Enterprise recovers the pitted and burned emergency buoy from the wreckage of Valiant which penetrated the odd energy barrier that surrounds the galaxy. Garbled recordings suggest odd consequences of that journey, and even that Valiant's own captain ordered her destruction. Enterprise also visits the barrier, and it has odd effects on certain members of the crew with high esper ratings. One in particular, Kirk's friend Gary Mitchell, appears to have developed nearly godlike mental and physical abilities, and lost his moral compass as well. Now Kirk must discover how to stop - and maybe kill - his old friend before that becomes impossible, and Mitchell goes on to conquer the Federation!
Episode: 1x04 | Airdate: Sep 29, 1966
Psi-2000 is a lifeless, frozen world in the final stages of planetary disintegration, an invaluable opportunity for scientific study. But the enter scientific outpost complement is dead, apparently by violence. And soon enough, an odd intoxication of similar nature begins sweeping through Enterprise, threatening all of the crew and even the ship itself, as intoxicated crewmen lose all sense of duty and purpose. Worse, McCoy's investigations reveal no causative agent, limiting his ability to treat those affected.
Episode: 1x05 | Airdate: Oct 6, 1966
An odd, yellowish ore with magnetic properties on a crewman's clothing affects the transporter, and when Kirk is subsequently beamed up, he is split into two "halves". One half of him possesses his benevolent qualities, but is indecisive. The other possesses his malevolent qualities, but is afraid. At first the crew is unaware of the problem, and Kirk's reputation suffers. Then they realize what has happened, and that the transporter is useless - just when they need to bring back the remaining planetary expedition before the sub-zero night kills them! And they must discover how to "reassemble" the captain when it becomes clear that neither half can survive for long without the other.
Episode: 1x06 | Airdate: Oct 13, 1966
The Enterprise recovers Harcourt Fenton Mudd from within an asteroid belt. His crew is also his cargo - wives for settlers on Ophiuchus III. These women are very beautiful, and have oddly compulsive effects on the male crewmembers. Having burned out most of her dilithium crystals protecting Mudd's ship, Kirk detours to a Rigel mining colony to secure more. But Mudd's women secure a communicator for him, enabling him to strike his own deal with chief miner Ben Childress and his associates. To obtain the crystals, Kirk must bring down Mudd's women, and must agree to dismiss charges against Mudd. Added to the mix is that the women may not be all they appear to be...
Episode: 1x07 | Airdate: Oct 20, 1966
Roger Korby, described as the "Pasteur of archaeological medicine" has built a reputation recovering the knowledge of dead alien civilizations, until five years ago when his entire expedition was lost on the frozen world Exo III. Or was it? When Enterprise assumes orbit, someone using Korby's voice responds to their hails. It seems Korby discovered that the civilization of Exo fled their ice age by going underground. He has uncovered some of their science, including their machinery for producing hardy androids - and for transferring a consciousness into such a machine. And he has plans for that technology. Ambitions, sinister plans...
Episode: 1x08 | Airdate: Oct 27, 1966
Enterprise discovers a planet identical to Earth, with a very important exception: a few centuries earlier, a devasting plague struck. All of the adults were killed, but the children somehow survived - and still survive, hundreds of years later, feral and deeply distrustful of "grups". And there are monsters: insane, covered with scab-like plaques, they attack on sight. The disease is still active; the plaques appear on the landing party. If McCoy cannot discover a cure in the week they have left, all will die. Even Spock, now a carrier, cannot return to the ship.
Episode: 1x09 | Airdate: Nov 3, 1966
Enterprise stops at the Tantalus penal colony to deliver drugs and collect research materials. Except that the research materials box contains a dangerous madman, Simon van Gelder - the former director of the colony. Kirk and psychiatrist Helen Noel beam down to speak with Tristan Adams, to learn what happened to van Gelder. It seems Dr. van Gelder was the victim of a new device, a neural neutralizer. But was what happened really an accident, or something more sinister?
Episode: 1x10 | Airdate: Nov 10, 1966
Mapping star systems, Enterprise encounters an odd cube. Apparently solid, it senses the ship, moves to block it - and when Enterprise attempts to disengage, pursues while emitting dangerous radiation. Kirk is forced to order its destruction. He probes farther, to find the builders of the device. And he does, when the Fesarius appears. The immense flag ship of the First Federation and her captain, the enigmatic Balok, regard the destruction of the cube as an aggressive act, and determine that the crew will be imprisoned and the ship destroyed.
Episode: 1x11 | Airdate: Nov 17, 1966
Spock diverts the Enterprise to Starbase 11, where Kirk discovers that Spock's former commander, Christopher Pike, has been seriously injured and disabled by exposure to delta rays, experienced while saving a class of cadets. Pike is now confined to an elaborate life support apparatus. Spock abducts Pike and locks the Enterprise on a course for Talos IV, the only planet subject to General Order 7: visiting the world is a capital crime. Spock refuses to explain his actions, but demands a court martial, during which he presents evidence of an earlier visit. War, thousands of centuries ago, devastated the planet, and it was only now becoming able to support life again. Its inhabitants, forced underground, had developed enormous mental powers, including the ability to place illusions within the minds of others. Their plan was to breed a race of slaves to help them reclaim their world, as they were fragile and their civilization degenerate: illusions had proved a kind of narcotic. To this end, they kidnapped Captain Pike years ago...
Episode: 1x12 | Airdate: Nov 24, 1966
As the court martial continues, Kirk learns the Talosians meant to breed Pike with an earlier survivor, Vina, to produce their slave race. But Pike convinces them that Earthmen would prefer death to such slavery, however pleasant illusions could make it. Humans were the Talosians last chance, but Pike convinces them to release him. Finally, as they orbit Talos, Kirk learns why Spock violated General Order 7: here, in his illusory world, Pike can live out his remaining years as the man he once was. The Talosians agree to this, and the Federation suspends General Order 7 due to the circumstances.
Episode: 1x13 | Airdate: Dec 8, 1966
Dr. Leighton calls Enterprise to his home on Planet Q with the promise of a new food source that could end hunger. But this is a ruse: Leighton is one of the few remaining survivors of Kodos the Executioner, who used a planetary famine to apply his own ideas of eugenics on Tarsus IV years earlier. A burned body convinced authorities that Kodos had died then, but Leighton is certain that actor Anton Karidian is Kodos. Kirk is less than amused at the deception - and then someone murders Leighton. It's not enough to accuse, but it is enough for suspicion, so Kirk arranges to strand the acting troupe, and then offers them a ride on Enterprise where he hopes to ascertain whether Leighton's accusation is true.
Episode: 1x14 | Airdate: Dec 15, 1966
The Enterprise tries to intercept a Romulan warship that is testing the Federation's defenses along the Neutral Zone separating the two.
Episode: 1x15 | Airdate: Dec 29, 1966
Enterprise visits an idyllic planet, where McCoy encounters a large white rabbit that is "very late". And shortly afterwards, a little girl who is following him. McCoy isn't becoming insane; it soon becomes apparent that thinking about a thing will cause it to materialize, as everyone encounters people and things from their past or their fantasies. But something on the planet's surface is draining power from Enterprise. And then McCoy, convinced that what he sees is a harmless illusion, confronts a charging knight - and dies, pierced through the heart! What kind of odd world is this, and how can the ship and crew escape it?
Episode: 1x16 | Airdate: Jan 5, 1967
Enterprise is en route to the New Paris colony to deliver much needed medical supplies, needed to counter a plague. It passes Murasaki 312, a quasar-like system. Since there is time, Kirk's standing orders require him to dispatch a scientific team to study the phenomenon. The expedition immediately runs into trouble, pulled of course and forced to an emergency landing on Taurus II, then beset by the hulking, homicidal natives of that planet. Can Spock's purely logical approach to leadership save the expedition and reunite its members with Enterprise?
Episode: 1x17 | Airdate: Jan 12, 1967
Within a "star desert" the crew encounter the odd, storm-wracked planet Gothos. Then Kirk and Sulu disappear from the bridge. The planet's sole inhabitant is the foppish Trelane, who lives in a manor house be believes represents modern Earth, but which is actually centuries out of date. He has plans for the crew, and the power to ensure that he gets what he wants. Kirk manages to thwart him, but it's only temporary: Trelane moves Gothos itself to intercept the fleeing starship! Against that kind of power, Kirk will need all his wits...
Episode: 1x18 | Airdate: Jan 19, 1967
Enterprise stops at Cestus III, there to visit Commodore Travers, who enthusiastically invites Kirk to bring his key people to the surface. Beaming down, Kirk discovers the outpost has been destroyed! The landing party comes under attack, but Kirk and Spock recover a powerful ballistic weapon and strike back. The aliens flee, with Enterprise in hot pursuit, into an unknown region of space. There, both ships are paralyzed by an "unidentifiable power" from the distant star system of the Metrons, and both captains are transported to a world where they may engage in hand to hand combat to determine the fate of their respective ships. But is that the whole story?
Episode: 1x19 | Airdate: Jan 26, 1967
A "black star" slingshots Enterprise back in time, to the 1960s, in Earth orbit. She appears almost directly above a military base, which draws all sorts of unwelcome attention. The base dispatches Major John Christopher to look. Enterprise attempts to keep him at bay with the tractor beam, but his aircraft is too fragile to withstand the beam and disintegrates, forcing Enterprise to beam Christopher aboard. Now they have disrupted history. Christopher himself is not historically significant, but his son is. He must be returned, but how?
Episode: 1x20 | Airdate: Feb 2, 1967
Enterprise encounters an ion storm, which requires an observer in the ion pod. Top of the duty roster is Commander Ben Finney, who is tragically lost when Kirk must eject the pod as part of the Red Alert protocol. At the starbase, Commodore Stone discovers that the computer records tell a different story: that Kirk ejected the ion pod during Yellow Alert, and that if he had waited properly, Finney might still be alive. He offers Kirk a chance to resign his commission "for the good of the service", but Kirk refuses - and so draws a general court martial. His advocate? The quirky Samuel Cogley, who eschews his computer in favor of books.
Episode: 1x21 | Airdate: Feb 9, 1967
Six thousand years ago, the planet Beta III was torn apart by war, crime, and corruption. Then a visionary leader arose, Landru, who became a benevolent autocrat. He has maintained a simple, stable society that has survived since then without those "ancient evils". Enterprise is there to investigate the disappearance of the starship Archon in the vicinity a century earlier. It seems that Landru dislikes those who display individuality; they must be absorbed into "The Body" or destroyed. So it was with the "Archons" and so it will be with the Enterprise unless Kirk can defeat Landru. But will unseating him destabilize the society? Will it be a violation of the Prime Directive?
Episode: 1x22 | Airdate: Feb 16, 1967
The Enterprise chances across a DY-100 class ship, launched from Earth "in the 1990s". It carries around seventy people, who have been hibernating since their launch. The ship's systems revive the leader, whom Kirk soon learns is Khan Noonien Singh, the leader of a group of genetically enhanced "supermen" who nearly took control of Earth during the Eugenics Wars. They have essentially fled to the future, and with their capabilities, Khan plans to revive his campaign to place "superior" men in positions of leadership.
Episode: 1x23 | Airdate: Feb 23, 1967
Kirk and the Enterprise have been sent to establish diplomatic relations with the planet Eminiar VII, a planet that decidedly does not wish such relations! But Ambassador Fox insists they make the attempt. Planetside, they learn Eminiar has been fighting a war with Vendikar, another planet in the same system, for five hundred years - a war fought entirely by computers, with casualties required to report to disintegration machines for tidy disposal. And the Enterprise has been declared a casualty of a "tricobalt satellite explosion"; her crew must likewise report for disintegration so their deaths may be recorded and reported to Vendikar.
Episode: 1x24 | Airdate: Mar 2, 1967
The Federation established a colony on Omicron Ceti III before it knew that the system's star emitted Berthold Rays, which degrade animal tissue. Tolerable for short periods with precautions, these rays spelled doom for the colony. So how are they still alive, and in better health than when they left Federation space? And perhaps more importantly, why have they accomplished... nothing? The answer threatens the Enterprise...
Episode: 1x25 | Airdate: Mar 9, 1967
Miners on the mineral rich world of Janus II have begun to die horribly, burned to a crisp by the effects of a powerful corrosive. The Federation depends on these mines to supply minerals to many other worlds, so it sends Kirk and the Enterprise to investigate. But a starship, as one miner acerbically comments, cannot enter the mining tunnels. Kirk and Spock will have to use their wits to solve this problem. And they'll have to do it quickly, since the same agency has sabotaged the antique pergium reactor that maintains life support.
Episode: 1x26 | Airdate: Mar 23, 1967
Kirk and Spock transport to the planet Organia, a pastoral realm of very low technology, which has the misfortune of being strategically important to the Klingons, who plan to use Organia as a forward base when they war on the Federation. Despite Kirk's best efforts, he cannot seem to impress upon the Organians that they are in dire peril and should ally with the Federation. Then the Klingons arrive, and being imposing martial law, and taking and executing hostages. Kirk works behind the scenes to interfere, but when the Organians betray him to the Klingons, he starts to wonder if they are worth protecting.
Episode: 1x27 | Airdate: Mar 30, 1967
An alien named Lazarus is somehow responsible for a kind of "winking out" effect - all of reality seems on the verge of collapse. He is fleeing a monster whose intent is nothing less than the destruction of reality. But through a mishap, Kirk is transported to the home of that monster. And he looks exactly like Lazarus! Kirk must decide which of them - if either - is the monster. If he guesses wrong, it's the end of everything.
Episode: 1x28 | Airdate: Apr 6, 1967
Ripples in time have provoked the curiosity of the Enterprise crew. One such ripple shakes the ship and gravely injures Sulu. McCoy brings him back from the brink with a powerful drug, but another ripple results in a tragic overdose, afflicting McCoy with dangerous paranoia! He beams down to the planet - the transporter was locked onto the source of the time disturbances. On the surface, he evades the landing party long enough to flee - into the past, where his psychosis results in him somehow erasing the Federation, and the Enterprise, save only the landing party. Their one chance is to use the same artifact - the self-styled Guardian of Forever - to arrive before McCoy and prevent him from changing their history.
Episode: 1x29 | Airdate: Apr 13, 1967
Approaching the planet Deneva, the Enterprise encounters a private spacecraft whose pilot is flying desperately into the sun, the apparent act of a lunatic. Spock reveals disturbing news: a pattern of mass insanity that has spread across the galaxy in a nearly straight line, the current end of which is Deneva. The landing party discovers the horrifying truth - and one of them becomes its victim. Now the crew must devise a cure before Spock dies, or is driven hopelessly insane.
Episode: 2x01 | Airdate: Sep 15, 1967
Spock is becoming increasing irrational, even threatening to break McCoy's neck! He can't or won't explain this behavior to Kirk, only asking to return to Vulcan. It's a request Kirk cannot grant, given the Enterprise's other business. Until McCoy tells him if Spock continues to deteriorate, he will die in days! Kirk makes the decision to take his friend back to his home world, where he learns that Spock's problem has to do with marriage...
Episode: 2x02 | Airdate: Sep 22, 1967
Enterprise nears the planet Pollux IV, when an immense humanoid hand appears and seizes the ship! It is not actually living tissue, but a complex field of energy. And it belongs to a being who claims that he and his kind visited Earth long ago, and were then revered as gods - in this particular case, the Greek god Apollo. His request is a simple one: the crew of the Enterprise will depart the ship and establish a colony of worshippers. Of course, Kirk has no intention of doing this; he must make "Apollo" understand that humans have moved past him.
Episode: 2x03 | Airdate: Sep 29, 1967
A space probe of immense power and sophisticated technology has apparently annihilated the entire Malurian civilization, and now threatens Enterprise. But when Kirk hails it, the attacks cease and it allows itself to come aboard. Soon enough, the reason for its forebearance is revealed: it mistakening believes Kirk is its creator, Jackson Roykirk. This probe is Nomad, launched from Earth long ago. But its technology is far beyond what was understood then; beyond even what the modern Federation is capable of. What happened to Nomad, and why does it destroy whole civilizations?
Episode: 2x04 | Airdate: Oct 6, 1967
The Halkans are a people deeply committed to peace. Kirk is trying to negotiate with them for dilithium, the rare mineral that's needed for warp power systems. But if there is even a chance their crystals will be used for violence, they cannot agree. Kirk beams back to his ship as a magnetic storm approaches - but the ship where he materializes is vastly different, run by savage opportunists, sadists, and killers. This ship, part of an Empire, will wipe the Halkans from their world and seize their crystals. Kirk must find a way to prevent that, and to return himself and his landing party home.
Episode: 2x05 | Airdate: Oct 13, 1967
Gamma Trianguli VI is a peaceful planet with abundant plant life. It seems a paradise, but the landing party soon feels the thorns: poisonous plants, killer storms, and explosive rocks all claim lives. Eventually, they discover a small community of primitive people who serve the mysterious Vaal, an immense statue, chiefly by feeding it when it demands this. These people live immensely long lives, and do not age or procreate unless there is an accident. Theirs is a stagnant society, and into the bargain Vaal apparently has the means to attack the Enterprise...
Episode: 2x06 | Airdate: Oct 20, 1967
Enterprise discovers the wreck of Constellation, a sister ship. The only survivor is Matt Decker, the Captain. He reports beaming his crew down to the fourth planet - except that there is no fourth planet! He investigated an odd occurrence: a planet apparently disintegrating, and discovered an immense space vessel cutting the planet apart with an antiproton beam, and digesting the pieces! This machine came from outside the galaxy, a relic of a devastating war fought long ago and far away. It will carve a path of destroyed solar systems through the most populous part of the Milky Way unless Kirk and his crew can stop it.
Episode: 2x07 | Airdate: Oct 27, 1967
Sulu, Scotty and Jackson explore Pyrus VII, and then Jackson calls the ship, "one to beam up". He materializes dead, and a sepulchral voice threatens Kirk, saying his ship is cursed! Beaming down, Kirk discovers his men enslaved by strange aliens, who have created a Gothic castle and other artifacts straight from Halloween. But their power and threat are real - they are from a place so alien, that the sensations of this universe are intoxicating. If not stopped, they pose a grave threat to the Federation.
Episode: 2x08 | Airdate: Nov 3, 1967
Mr. Norman is a new crewmember whom McCoy finds off-putting. He acts like a Vulcan, which is odd in a human. There's a good reason: Mr. Norman is not human. He is one of a collection of androids sent to hijack Enterprise by Kirk's old adversary, Harcourt Fenton Mudd! Mudd has plans for the starship, grand plans. And so do the androids.
Episode: 2x09 | Airdate: Nov 10, 1967
Enterprise sends a shuttlecraft to retrieve Federation Commissioner Nancy Hedford, who suffers from Sakuro's Disease, so that she may be treated. The craft is pulled off course and lands on a small planetoid, where the crew discover the systems will not work. They also discover a man, apparently living alone there - or, is he? He seems to from time to time commune with an energy cloud, the alien being responsible for forcing the shuttlecraft down. It means for the crew to serve as companions for the man - forever.
Episode: 2x10 | Airdate: Nov 17, 1967
A large diplomatic conference will take place on Babel, to discuss the contentious issue of whether to admit Corridan to the Federation. Delegates are divided, and some of their motives are less than pure. Among these delegates is Sarek of Vulcan - Spock's estranged father. Add a mysterious challenging spacecraft and a murderer aboard the Enterprise, and Kirk has his hands full. Then Kirk himself is stabbed, leaving him seriously injured at the very moment when Spock is due to donate blood so that McCoy can operate on Vulcan ambassador Sarek's damaged heart. The key to solving this puzzle will require deducing which of the many factions is willing to go to violent lengths to sabotage this conference.
Episode: 2x11 | Airdate: Dec 1, 1967
The Federation sends Kirk to negotiate for mining rights with Aka'ar, Te'er of the Ten Tribes of Capella IV. Capella IV has deposits of the rare mineral topaline, needed for life support systems. The Klingons need this mineral, too, and their presence creates tension further complicated by conflict among the members of the tribe. Ma'ab murders Aka'ar and becomes the new Te'er, and he has a decidedly different attitude that favors the Klingonm perspective. Worse, Kirk and McCoy will not stand by while he murders Ele'en, the pregnant wife of the old Te'er, despite this being Capellan tradition. Soon enough, the Federation party is running for the hills - literally - with Capellans and a Klingon in pursuit.
Episode: 2x12 | Airdate: Dec 8, 1967
Enterprise discovers the scientists on Gamma Hydra IV are all either dead or dying of old age, despite the fact that the oldest was around thirty! Matters get worse when the landing party begins to show signs of aging, all except for Chekov, who is mysteriously unaffected. Eventually, Kirk must be relieved of command, and as Spock and Scotty are both affected, Commodore Stocker assumes command. But Stocker has been a desk officer his entire career; he has no field experience, which leads him to make a desperate, wrong decision...
Episode: 2x13 | Airdate: Dec 15, 1967
On an obscure planet, Kirk smells something that reminds him of the past. And then two crewman die, their ghastly pallor betraying the fact that every red blood cell in their bodies has been destroyed, the hemoglobin neatly removed. A long time ago, very far from here, Kirk was a young Lieutenant about the Farragut when that ship encountered the cause: a mysterious, gaseous cloud that feeds on blood. Now, Kirk is obsessed with destroying the monster that killed his then mentor, the Farragut's captain Garrovik. Perhaps to an unhealthy degree. Or, given what Spock discovers, perhaps not.
Episode: 2x14 | Airdate: Dec 22, 1967
Kirk takes Scotty to Argelius, a planet renowed for hospitality. Scotty is still recovering from serious injuries accounted to a female member of the crew, so McCoy is concerned he might harbor subconscious resentment toward women. But apparently not; he takes a young woman for a walk through the fog. Kirk and McCoy leave later, and en route to another tavern, hear a high scream. They arrive to find Scotty, bloody knife in hand, standing over the body of the young woman, who has been stabbed dozens of times! They're certain Scotty is innocent despite the evidence, but proving that will require them to discover the actual murderer - and reveal a horrifying truth from history!
Episode: 2x15 | Airdate: Dec 29, 1967
Under the terms of the Organian Peace Treaty, Sherman's Planet will become a colony of whoever can best develop it. To that end, the Federation intends to ship a large quantity of quadrotriticale to that planet, and Federation Undersecretary Nilz Baris is determined that the grain will arrive, so he orders the manager of Space Station K-9 to issue a distress call! Enterprise responds to discover no emergency; Baris just wants guards for his grain. And then a Klingon ship arrives, seeking shore leave. And Cyrano Jones, an itinerant trader, also arrives, with some odd animals he calls tribbles. Some very hungry, odd animals...
Episode: 2x16 | Airdate: Jan 5, 1968
Kirk, Uhura and Chekov are set to beam down to examine and maintain a communications relay station, when they vanish from the transporter room in a way inconsistent with normal transport! They have been whisked across planetary systems by the mysterious Providers, who gather "inferior" beings from all over the galaxy and pit them against each other in blood contests. This activity is the only thing that stimulates the Providers. As the three begin their involuntary training, Enterprise begins following the scant evidence their abductors left behind, trying to locate them.
Episode: 2x17 | Airdate: Jan 12, 1968
The Horizon visited the planet Iotia a hundred years ago, long before the Prime Directive forbid interference in pre-warp alien cultures. Beaming down to investigate the damage, Kirk, Spock and McCoy discover a culture run by mobsters! It seems that Horizon left behind a book, "Chicago Mobs of the Twenties", and the highly imitative people of Iotia patterned their society after the groups described in its pages. How can Enterprise undo the grievous harm Horizon did to this civilization?
Episode: 2x18 | Airdate: Jan 19, 1968
Spock senses the crew of Intrepid, a starship crewed solely by Vulcans, die. Enterprise investigates, and discovers a zone of darkness which conceals the hazard: an immense yet single-celled organism which drains energy from anything it encounters, as it did the Intrepid and her crew. And unless they can discover how to destroy it, Enterprise will be next. Worse, there are signs the organism has accumulated sufficient energy to reproduce...
Episode: 2x19 | Airdate: Feb 2, 1968
Kirk returns to a planet he surveyed years ago as a younger officer. There he discovers that the villagers and the hill people are now fighting, because the villagers have developed crude firearms and the idea that they should simply take anything they want from the hill people. Worse, Spock is the victim of a gunshot! Kirk and McCoy return to the surface to investigate more completely, but Enterprise must leave to avoid detection - and then a mugato bites Kirk! He must make contact with the hill people, who number among them a kind of witch doctor called a kanutu, who may be able to help. But that help comes with a price...
Episode: 2x20 | Airdate: Feb 9, 1968
Enterprise responds to odd readings, which lead the crew to a planet similar to Earth, except that it is much older, and a cataclysm stripped its atmosphere away a half million years ago; it has been dead ever since. But from somewhere on that world comes a voice. Something has evidently endured 500,000 years - the last survivors of the civilization that flourished here. And all they want are the bodies of a few humans...
Episode: 2x21 | Airdate: Feb 16, 1968
Historian and sociologist John Gill has stopped responding to transmissions. He is embedded in the Ekosian population to study it. Investigating, Kirk and Spock discover that Ekos has developed nuclear weapons - an achievement well ahead of where they should be scientifically, based on past probes. And they have modeled their society on Nazi Germany, right down to oppression of their sister planet, Zeon. It seems apparent Gill has contaminated this society, but why? And why Nazi Germany?
Episode: 2x22 | Airdate: Feb 23, 1968
Kelvans from the Andromeda galaxy have discovered that rising radiation levels will make their galaxy uninhabitable within ten millenia. So they have dispatched generation ships of soldiers to nearby galaxies to see which of them they might conquer. Enterprise encounters such a group when her crew answers a distress call. With the Kelvans' superior technology, they may well be able to conquer the entire Milky Way galaxy!
Episode: 2x23 | Airdate: Mar 1, 1968
Enterprise discovers her sister ship, Exeter in orbit around a planet, unresponsive. Kirk, Spock and McCoy beam aboard and discover only empty uniforms mixed with a handful of crystals. Then they find a log - the ship is infected with a deadly plague! Their only chance is to beam down to the planet's surface immediately. There, they discover heartbreaking evidence that Exeter's captain Ronald Tracy has violated the prime directive, up to and including mass murder. But he has what he believes is a good reason - and it depends on McCoy's research into a long ago bacteriological war.
Episode: 2x24 | Airdate: Mar 8, 1968
Enterprise is chosen as the testbed for the revolutionary M-5 computer. The machine's inventor, Richard Daystrom, claims it can take control of a starship, freeing men for less dangerous and more rewarding work. It all depends on whether his breakthrough technology, multitronics, is as powerful and capable as he says. After a few exercises, Spock begins to wonder exactly how multitronics works - for the M-5 does not react as computers typically do.
Episode: 2x25 | Airdate: Mar 15, 1968
The Enterprise follows the wreckage of the S.S. Beagle to a planet where they discover an Earth-like civilization, except that Rome never fell, and rules a world much like twentieth century America. Intercepted radio transmissions suggest deeper mysteries, so Kirk, Spock and McCoy beam down to investigate, and then find themselves caught between the Roman government and a group of "sun worshippers". Proconsul Claudius wants Kirk to beam down his entire crew; the Proconsul is determined that no one will leave this world!
Episode: 2x26 | Airdate: Mar 29, 1968
The Enterprise has used the "light speed breakaway" technique to travel to Earth in the year 1968, to study how humans survived the desperate problems of that era. Then, they intercept a man beaming back to Earth from at least a thousand light years away, a technical feat beyond even Federation science! Who is Gary Seven, how did he get access to such advanced technology, and why has he come to Earth? He has a story, but Kirk has trouble believing it. Worse, he has trouble knowing whether he should allow Seven to pursue his agenda, or try to stop him. One of those choices is certain to destroy the future... but which?
Episode: 3x01 | Airdate: Sep 20, 1968
An alien woman materializes on the bridge of the Enterprise and knocks the command crew unconscious. When they come to, they discover that Spock's brain has been stolen and they have to race against time to track her down and recover the brain in order to save Mr. Spock.
Episode: 3x02 | Airdate: Sep 27, 1968
Captain Kirk acts strangely and ends up taking the ship into the Romulan neutral zone where they are surrounded by Romulans, the Romulan commander then takes a interest in Mr. Spock.
Episode: 3x03 | Airdate: Oct 4, 1968
Mr. Spock must destroy an asteroid threatening a primitive world where lost and amnesiac Captain Kirk has taken a wife.
Episode: 3x04 | Airdate: Oct 11, 1968
A group of orphaned children under an alien's control take over the minds of the Enterprise crew.
Episode: 3x05 | Airdate: Oct 18, 1968
Only a jealous scientist can save Spock when he goes mad after seeing a hideous Medusan.
Episode: 3x06 | Airdate: Oct 25, 1968
Powerful aliens transport the Enterprise officers into an illusionary re-creation of the gunfight at the OK Corral.
Episode: 3x07 | Airdate: Nov 1, 1968
An alien which feeds on violence traps Klingons and Enterprise crewman together.
Episode: 3x08 | Airdate: Nov 8, 1968
After Dr. McCoy informs Captain Kirk that he is dying, the Enterprise crew discovers a planetoid that is on a collision course with a inhabited world. Kirk, Spock and McCoy beam down and discover it is a populated space ship where most of the inhabitants having no clue they are on a space ship.
Episode: 3x09 | Airdate: Nov 15, 1968
Kirk is trapped on a disintegrating star ship and drifts between dimensions while the Tholian's create a energy web around the Enterprise to prevent them from escaping.
Episode: 3x10 | Airdate: Nov 22, 1968
Rulers of a culture modeled after Platos Republic kidnap Kirk, Spock and Dr. McCoy.
Episode: 3x11 | Airdate: Nov 29, 1968
The dying Scalosians, invisible to humans, need the Enterprise crew to help repopulate their decimated planet.
Episode: 3x12 | Airdate: Dec 6, 1968
After arriving at a outpost to pick up the two members of a science team, Kirk, McCoy and Spock find the team missing. They are then transported to another location by alien beings who use them in a torturous experiment involving a young girl who does not speak.
Episode: 3x13 | Airdate: Dec 20, 1968
Klingons interfere when the Enterprise is ordered to transport an unwilling royal bride to her wedding in another star system. During the trip, the enterprise is sabotaged.
Episode: 3x14 | Airdate: Jan 3, 1969
Inmates gain control of an insane asylum, taking visiting Kirk and Spock prisoner.
Episode: 3x15 | Airdate: Jan 10, 1969
A feud that is thousands of years old between sworn enemies threatens to destroy the Enterprise.
Episode: 3x16 | Airdate: Jan 17, 1969
Captain Kirk suddenly finds himself on what appears to be the Enterprise, alone except for a beautiful alien woman while on a away mission to the planet Gideon.
Episode: 3x17 | Airdate: Jan 24, 1969
The Enterprise discovers a planet that defies the conventional theories of planetology, so Kirk, Sulu, McCoy and D'Amato (a geologist) beam down to investigate. As they depart, a mysterious woman appears in the transporter room and attacks the chief there. Then the Enterprise is hurled nearly a thousand light years away! The strange female apparition reappears, and demonstrates that she is a grave threat to both stranded crew and the ship...
Episode: 3x18 | Airdate: Jan 31, 1969
A mysterious storm has inflicted heavy - perhaps irreparable - damage on the library planetoid Memory Alpha. And it seems to have a curious affiliation with new crewmember Myra Romaine. As the Enterprise pursues the hazard, Romaine falls more under its influence, and the crew learns is is not a storm at all, but a form of life that means to survive at ANY cost.
Episode: 3x19 | Airdate: Feb 14, 1969
Rigelian Fever rages about the Enterprise; on a small planet named Holberg 917G, the crew has discovered a source of the only cure, ryetalin. Kirk, Spock and McCoy beam down, and discover the planet is the private property of Flint. At first uncooperative, Flint relents and permits the crew to gather the material. But events soon have them wondering about Flint's real goals, and his mysterious ward, the enchanting Rayna.
Episode: 3x20 | Airdate: Feb 21, 1969
The Enterprise intercepts a stolen space yacht, whose thieves destroy it rather than face capture. But they are captured, and revealed as "counterculture" individuals looking for a mysterious planet they call Eden. Led by an insane genius, they manage to capture the Enterprise long enough to direct it to Eden, which is located in the Romulan Neutral Zone! And to make their escape, they create a lethal trap for the crew.
Episode: 3x21 | Airdate: Feb 28, 1969
The planet Merek II is gripped by a botanical plague. The only cure is the mineral zeenite, and the only practical source of that is Ardana. But Ardana has a stratified city: the troglytes who labor live in harsh conditions, while philosophers and artists enjoy the beauty of its floating city, Stratos. One among the troglytes, Vanna, means to change this, and plans to exploit the crisis - and Federation representatives Kirk and Spock - to accomplish that.
Episode: 3x22 | Airdate: Mar 7, 1969
The Enterprise surveys the planet Excalbia. As its surface is the temperature of molten rock, no landing party is possible, so when the orbital survey concludes, Kirk orders the ship to leave. And then... Abraham Lincoln appears, and at the same time a region forms on the planet suitable for human life. Kirk and Spock beam down and discover Yarnek. It seems the Excalbians are struggling to understand the concepts of good and evil; the help themselves they have constructed an experiment: four examplars of good, including Kirk and Spock, will battle four exemplars of evil, notorious figures from history. And if good loses, the Enterprise will be destroyed...
Episode: 3x23 | Airdate: Mar 14, 1969
While trying to locate the missing population of a planet doomed by a coming nova, Kirk, Spock, and McCoy find a mysterious librarian who sends them back into the planet's past. While Spock and McCoy fight for survival in a frigid landscape, Kirk is accused of witchcraft.
Episode: 3x24 | Airdate: Jun 3, 1969
Janice Lester, a lover from Kirk's past, uses alien technology to switch her consciousness into his body and vice versa, so that she can take command of the Enterprise and become a Starfleet captain as she always wanted.
Episode: S01 Special | Airdate: Jun 24, 1964