On an isolated asteroid, Kirk finds Zefram Cochrane, inventor of the warp drive, who has been missing for 150 years.
Kirk, Spock, and McCoy are ferrying Federation Commissioner Nancy Hedford back to the USS Enterprise. The commissioner, who has been called upon to prevent a war on Epsilon Canaris III, has developed Sakuro's Disease, a rare life-threatening illness, and must be removed to a medical facility for treatment. The commissioner is bitter at what she regards as incompetence in the Federation Medical Department, which she believes should have properly prepared her.
En route (shortly past point 3, on course 201 Mark 15), the shuttlecraft Galileo encounters a phenomenon that Spock describes as "vaguely like a cloud of ionized hydrogen, but with strong electrical impulses". Moving at warp speed, it envelops the shuttlecraft and disables its systems. The craft is pulled to course 98 Mark 12, towards the Gamma Canaris region.
There, it is soft-landed on an iron-nickel planetoid with a standard oxygen-nitrogen atmosphere and standard gravity – a place entirely suited for Human life. Examining the shuttlecraft, Spock discovers something that should be impossible: nothing is damaged, but nothing works. McCoy notes that the gaseous cloud they encountered in space seems to be here, on the surface. Then a loud "hallooooooo" breaks the stillness. Someone else is here – a young man who quickly joins the stranded group. He introduces himself as Cochrane. He tells the officers that a damping field prevents some technology here from working. But he denies knowledge of the force that brought the shuttlecraft here.
Kirk finds this man familiar, somehow. Cochrane shows his visitors to his home, decorated with instruments Kirk regards as antiques. Ominously, Commissioner Hedford has developed a fever, the first symptom of her illness.
Finally, Kirk presses Cochrane, and learns about the Companion. This is what he calls the strange creature that brought the Galileo here. Cochrane was old, and knew he wanted to die in space. So he took a spacecraft and left his home on Alpha Centauri for parts unknown. The Companion found him, reversed his aging process, and has maintained him here, ever since. Cochrane is responsible for the abduction of Kirk and his party; he communicated his loneliness in the hope that the Companion would free him, but instead it elected to bring him friends. Given these clues, Kirk also realizes why Cochrane seems so familiar: he is Zefram Cochrane, discoverer of the space warp.
Spock, meanwhile, is attempting to repair the Galileo when the Companion appears there. Curious, he touches it, and receives an electrical shock that knocks him cold. The circuitry of the ship bursts into flame; the Companion is taking no chances.
Cochrane agrees to summon the Companion, to see if it can help the commissioner, but learns that it cannot. While observing the Companion with Cochrane, McCoy and Kirk observe the apparent communion, and find it cannot be minimized to anything less than love, perhaps equating it in their minds with a sexual joining, something Cochrane alludes to later: "we've been close in a way that's hard to describe".
McCoy discovers Spock; the encounter has left Spock with a new insight: the Companion is largely made of electricity. Spock constructs a mechanism to scramble electrical impulses; with this, Kirk intends to disable or destroy the creature, so that the Humans may depart. Cochrane now has reservations; he doesn't want the creature killed. Kirk overwhelms him with the force of his personality. Unhappy at being forced into the role of a Judas goat, Cochrane nevertheless agrees to summon the creature. Spock throws the switch, and discovers that his mechanism is sufficient only to irritate the creature. It attacks Kirk and Spock, and despite McCoy's pleas, nearly kills them – before Cochrane calls it off.
Nearby, the Enterprise searches for the now long overdue shuttlecraft. Finally, at 210 Mark 40, the sensors detected a strong antimatter particle concentration. Lacking evidence that the shuttlecraft has been destroyed Scotty elects to follow this tenuous course.
On Gamma Canaris, Spock has completed modifying the universal translator so Kirk can communicate with the Companion. Among the first things they discover is that the Companion is female, casting its – her – relationship with Cochrane in an entirely new light. Kirk implores the Companion to permit their departure, but she is adamant; to her, the safety and health of Cochrane is the only important goal. And to ensure that, she intends to keep the shuttlecraft crew here, forever.
Cochrane is dismayed to discover the apparent sexual dynamic between himself and the Companion. He finds it repulsive. Kirk, Spock and McCoy do not understand his parochial attitude. For her part, the Commissioner is baffled by someone who, offered love, rejects it. The great regret of her life, as it draws near its end, is that she has never been loved.
The Enterprise continues its search. It has discovered an asteroid field containing 7,000 bodies in sizes ranging from A to M. Thirty percent of them have atmospheres in types ranging from H to M. The search will be a long one, but Scotty remains convinced by the lack of evidence that the shuttlecraft landed safely somewhere, and he is prepared to search every asteroid if necessary.
Kirk tries new tactics. First, he tries to convince the Companion that without challenges to overcome, the Humans will weaken and die. When that fails, he tries to convince the Companion that there can never be real love, because it and Cochrane are too different. The Companion considers this, and then disappears. Kirk's hope is that the Companion will release Cochrane and his party – love expressing itself as sacrifice – but this is not its choice. Instead, moments later, an apparently healthy Nancy Hedford appears in the door of Cochrane's small home.
The Companion has joined with her, sacrificing its immortality and its powers to become human, and experience life with Zefram Cochrane as a human woman would. Cochrane is reluctant, but becomes enthusiastic, promising to show her the galaxy. Sadly, she tells him that she cannot leave; her life emanates from this small planetoid. Just as he must eat, so she must remain here or perish. Cochrane cannot bring himself to leave her, and elects to remain behind. He asks Kirk to keep his existence a secret, a request Kirk grants.
- "Ship's log, stardate 3219.8. Lieutenant Commander Scott recording in the absence of Captain Kirk. A shuttlecraft bearing the captain, the first officer, Chief Surgeon McCoy, and Assistant Federation Commissioner Hedford is now definitely overdue for a rendezvous with the Enterprise. We are attempting to backtrack it."
- "Ship's log, stardate 3220.3. Lieutenant Commander Scott reporting in lieu of the captain and the first officer. We are continuing our search for the missing shuttlecraft."
"You're food to a starving man."
- - Cochrane to Hedford, as they are formally introduced
"I could even offer you a hot bath."
"How perceptive of you to notice that I needed one."
- - Cochrane and Hedford, as she ridicules his hospitality
"You wear your age very well."
- - Spock, complimenting Cochrane after realizing he is Zefram Cochrane
"Immortality consists largely of boredom."
- - Cochrane, after Kirk asks him if he wants to leave the planet
"What was it they used to call it? The Judas goat?"
- - Cochrane, before he baits the Companion
"Maybe you're a soldier so often that you forget you're also trained to be a diplomat. Why not try a carrot instead of a stick?"
- - McCoy to Kirk, on how to handle the Companion
"It's a big galaxy, Mister Scott."
- - Uhura, as the Enterprise searches for the missing shuttlecraft
"The idea of male and female are universal constants."
- - Kirk, explaining to Cochrane that the Companion is female
"You're not a pet. You're not a specimen kept in a cage. You're a lover."
- - McCoy, explaining to Cochrane his relationship with the Companion
"But I've never been loved. Never. What kind of life is that? Not to be loved, never to have shown love? And he runs away from love."
- - Hedford, on Cochrane's resentment toward the Companion
"This is loneliness. Oh, what a bitter thing."
- - The Companion as Hedford, after Cochrane recoils from her advance
"I can't leave her. I love her. Is that surprising?"
"Not coming from a human being. You are, after all, essentially irrational."
- - Cochrane and Spock, on Cochrane's decision to stay with the Companion
Story and Script
- Bantam Books published a series of novelizations called "foto-novels," which took photographic stills from actual episodes and arranged word balloons and text over them, to create a comic book formatted story. The fifth installment was an adaptation of this episode.
- This is the only episode in the first two seasons in which Captain Kirk is not on the Enterprise at any time during the plot. Likewise, the Enterprise does not appear until twenty-seven minutes into the episode. In four third season shows, Kirk also spends the entire episode off-ship: "The Paradise Syndrome", "Plato's Stepchildren", "Whom Gods Destroy", and "All Our Yesterdays".
- In the first draft script, Scotty is also on board the shuttlecraft (here called the Edison) with Kirk, Spock, McCoy and Hedford. It was originally he who was to encounter the Companion while attempting to repair the shuttlecraft.
- In the first draft, the Enterprise is temporarly commanded by Sulu, and the helmsman is an officer with an African background, named Lieutenant Ackrumba. The character later appeared in the novel Mission to Horatius.
- The first draft script ends with a joke: as the landing party leaves the planetoid, Spock wonders if Cochrane is a bigamist, by having two entities in the same body for his partner. Kirk assures him that this is nonsense.
- A Gold Key Comics comic book was released as a sequel to this episode, #49: "A Warp in Space".
- This is the first story to feature Zefram Cochrane, inventor of warp drive and an important figure to the Federation history. He would later re-appear in Star Trek: First Contact and ENT: "Broken Bow", played by James Cromwell.
- The Companion was designed by future Star Wars Oscar-winner Richard Edlund at Westheimer photographic effects company. (Star Trek Encyclopedia) The sparkling effects of the Companion would be reused in "The Apple" when the Enterprise fires phasers at Vaal, and again in "Obsession" inside of the deadly vampire cloud.
- The shuttlecraft mock-up is not the same as the set used for the interiors of the Galileo. Kirk and company are all crouching as they emerge from the ship, yet the shuttlecraft interior set had a lot more head room.
- The scenes of Cochrane communicating with the Companion were all shot at one time. The set was then completely redone with his house added for all of the sequences with Kirk and company. The inconsistencies between the two versions of the same set can be seen in alien trees that are near Cochrane in one view and absent in the next.
- Symbolically, the colored patterns in the scarf worn by the Commissioner are identical to the patterns in the energy field of the Companion. This is shown clearly as she looks at Cochrane through the scarf near the end of the episode. This wasn't scripted or even intended by the production staff. Director Ralph Senensky came up with the idea on the set, calling it "one of those wonderful freak accidents that happen".  The inspiration was a scene in "The Escape", a 1966 episode of The F.B.I., also directed by Senensky.
- A few scenes featuring Elinor Donahue had to be re-shot, because the original film negatives were damaged and couldn't be used. Portions of the planet set had to be rebuilt, since other episodes were shot there by that time, using different sets. Meanwhile Donahue got pneumonia and lost ten pounds. To hide this, they put Hedford's scarf around her neck and upper body. However, her weight loss is still visible on her face.  The re-shots were not directed by Ralph Senensky. 
- To give an illusion of open space to a confined stage set, wide angle lenses were used. Although Glenn Corbett appears to be hundreds of yards away when he first runs toward the shuttle, he is much closer. Strategically placed rocks also allowed the camera to be very far away without seeing the edges of the set.
- A drawback to the use of a wide angle lens is evident in the scene where actor Corbett first approaches the shuttlecraft. Accent lights on top of the set's background are clearly visible along the top of the "sky" as the camera pans to the right when following Corbett's path. At the end of the shot the black edge of the set is clearly visible behind the shuttlecraft.
- In a rare effect, slowly moving "clouds" were blown in from hidden vents, adding a touch of reality to the usually static planet set. This was also used in "Obsession".
- A view of the starship from dead center in front of the saucer section is used only in this episode.
- All the footage of the shuttlecraft in outer space was reused from "The Galileo Seven", some with the Companion animation added in post-production.
- The planet used as Gamma Canaris N (a purple color-corrected version of the planet created for "Operation -- Annihilate!", portraying Deneva) is reused in subsequent episodes, representing the Halkan homeworld in "Mirror, Mirror", Omega IV in "The Omega Glory" and Holberg 917G in "Requiem for Methuselah".
- Walter Koenig (Pavel Chekov) does not appear in this episode.
- Elizabeth Rogers, uncredited for some reason for her voice work as the Companion, returned to the series two times as communications officer Lt. Palmer.
- The original voice of the Companion was too emotionless and robotic, and all of her dialogs had to be re-recorded by another actress (apparently Rogers).
The remastered version of this episode premiered in syndication the weekend of 3 November 2007. It featured new shots of the Galileo and the Companion in space, replaced a foreground rock with a shot of the sky in Cochrane's initial appearance, and included the shuttle returning to the Enterprise in the closing shot. Curiously, the remastered version of the planetoid matches the purple sky of the sound stage less than the original. The original planetoid was all purple while the remastered version is brown with only a slight purple atmosphere.
- Story outline by Gene L. Coon, 7 April 1967
- First draft script, 19 April 1967
- Filmed: 10 May 1967 – 18 May 1967
- Score recording, 28 June 1967
- Original airdate, 10 November 1967
- Rerun airdate, 19 July 1968
- First UK airdate 11 May 1970
Video and DVD releases
- Original US Betamax release: 1986.
- UK VHS release (two-episode tapes, CIC Video): Volume 17, catalogue number VHR 2329, release date unknown.
- US VHS release: 15 April 1994.
- UK re-release (three-episode tapes, CIC Video): Volume 2.1, 3 February 1997.
- Original US DVD release (single-disc): Volume 16, 19 September 2000.
- As part of the TOS Season 2 DVD collection.
Links and references
2030; 2119; Alpha Centauri; antimatter; argon; asteroid; asteroid belt; automatic scanner; bath; brain wave pattern; cane; carrot; class M; commissioner; Companion's homeworld; computer central; dampening field; Earth; electricity; electronic scrambler; English language; Epsilon Canaris system; Epsilon Canaris III; Fahrenheit; Federation; fig tree; Galileo; Gamma Canaris region; gender; hydrogen; ion; iron; Judas goat; krypton; love; nickel; nitrogen; neon; oxygen; physicist; planetoid; probability; Sakuro's Disease; scientist; shuttlecraft; shuttlecraft bay; space warp; Starfleet; Starfleet Medical; symbiosis; tricorder; trident scanner; universal translator; volt; zookeeper
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