Executive Producer: Gene Roddenberry
Producers: Gene L. Coon + John Meredyth Lucas
Associate Producer: Robert H. Justman
Script Consultant: D. C. Fontana

Story by: John T. Dugan
Writer: Gene Roddenberry
Dir.: Ralph Senensky

Captain Kirk: William Shatner
Science Officer, First Officer, Cmdr. Spock: Leonard Nimoy
Dr. Leonard "Bones" Mc Coy: DeForest Kelly
Lt. Sulu: George Takei
Lieutenant Commander Montgomery Scott: James Doohan
Lieutenant Uhura: Nichelle Nichols
Nurse Christine Chapel: Majel Barrett
Dr. Anne Mulhall: Diana Muldauer
Voice of Sargon: James Doohan

Stardate 4768.3

Arret is a planet which was supposed to be dead. Nevertheless a distress call is coming from it, reaching the Enterprise. A voice calling itself "Sargon" welcomes the crew and asks for help. When Spock's computer's sensors measure where the source comes from, he finds it to be deep under the surface. Sargon assures them that all is prepared for human conditions and Spock confirms that it is. Just as captain Kirk puts together a landing party and Spock wants to come along, Kirk assures him he cannot do without him, but in this special case ... while he speaks the lights fade. By suggesting that Sargon might want Mr. Spock to come along, Kirk causes the reaction: All lights are back again. The others in the team are Dr. McCoy, Dr. Anne Mulhall and two guards. Sargon takes over the transmission because it is going through more than 1,000 miles of hard rock. As they arrive in the cave, they notice that the two guards have not been transmitted with them.

Spock's tricorder tells him that the room was built exactly at the time the surface of the planet got destroyed. In the adjoining room they meet Sargon. When Spock asks to use his tricorder on him, Sargon grants his permission and tells him that the only thing he will find is pure energy. Sargon is pure energy, "stored" in a round bowl of transparent, milky kind of glass. He explains that his people's history ended in destruction when their minds became too powerful. They fighted among themselves, causing the total annihilation of the planet, but tried to preserve some of the most valued citizens' essences, choosing them among all parties representatives. By now only three have survived: Sargon, his wife Thalassa and Hennoch, from the opposite party.

In answer to Kirk's question what kind of help Sargon is asking from them, Sargon takes over Kirk's body and the glass bowl seems to contain a less brighter light: captain Kirk. Sargon shows them the containers of the other two besides all the others which have ceased to exist and explains that they only want to borrow their bodies (Kirk's, Spock's and Dr. Mulhall's) until they have accomplished to build mechanical bodies for their own. In the conference room Kirk, Spock, Scotty, Dr. McCoy and Dr. Mulhall meet and discuss pros and cons of the exchange. Kirk wants all to give their consent or there is no help for Sargon and the others. Spock points out the advantage of knowledge they gain through the exchange.

No "no" is given. In the sick bay Spock, Kirk and Dr. Mullhall lie beside one of the round containers each. When the light inside dims, the exchange has been done. Hennoch, in Spock's body, wakes up and laughs. Looking at Sister Chapel he says: "Sleeping for half a million years and I’ve missed the best!" Thalassa wakes up and looks anticipating at Spock: "Sargon?" "Here I am," Sargon, in Kirk's body answers. Both are very happy to feel, breathe and touch each other again. Hennoch is glad about his body: "Spock's body's the best, if the Vulcan would fight against you, you'd have no chance!" "The Vulcans estimate peace very highly," McCoy replies. For Thalassa and Sargon it is too exhausting for their bodies and they need to go back, while Hennoch/Spock does fine. He prepares a medicine to make the exchange last longer and orders Sister Chapel to come with him. She notices that there is another substance in the third injection and wonders: "If the captain gets another substance, he'll die," Hennoch/Spock looks at her: "so, what?" and touches her forehead. She forgets.

I will prepare the medication ...	Sargon would not want to allow me to keep this body, that's why I am forced to kill your captain

When looking at the injections, Sister Chapel tries to remember something, but cannot, though she is trying very hard. Shortly later Dr. McCoy treats Kirk's body, after he had collapsed – only to announce his death. And Sargon didn't make it to his container, he was too far away, Dr. McCoy says. Meanwhile Hennoch tries to convince Thalassa to reject the robot-body the more ... by mentioning what they could make out of the robot with some additional hair etc... She directly goes to McCoy and offers help to get his captain back. She tells McCoy that she wants to live free amongst people. Blackmailing McCoy, she suggests that he keeps quiet about her not being Anne Mulhall and he gets Kirk back. McCoy refuses to be blackmailed and Thalassa tortures him with pain. Seeing him suffer Thalassa realizes that the temptation to use their power on others is too big. And she asks McCoy for forgiveness.

Suddenly they hear Sargon's voice: He'd expected that decision from her. Sargon had put his spirit into the material of the ship the same way they had intended to go into the robots. Now Thalassa brings back Kirk's mind into Kirk's body. When McCoy enters, he finds his captain - and the destroyed container of Spock's mind. The captain now orders a toxin to kill Spock's body. Meanwhile Hennoch/Spock has taken over the bridge and knows their intentions, because he can read their minds. He makes Sister Chapel inject the poison into McCoy's body. She injects it – into Spock's body. The moment he quickly wants to change into another body while Spock's body collapses, Sargon makes sure, he won't make it and destroys Hennoch. Beside the dead body of Spock, Kirk kneels down and mourns about his friend – there has been no other way. Sargon speaks to him, saying he'd never allow him to sacrifice his friend.

A light coming from Sister Chapel shines over to Spock and Spock gets up. "You are alive? In the injection there was poison enough for ten Vulcans," McCoy says. Sargon explains to him that, because Hennoch would have read his mind, he had to believe it was poisonous. Not to jeopardize Spock's body it only had been a tranquilizer, convincing enough for Hennoch to leave it. Spock was where Hennoch never would have expected him: in Sister Chapel's mind. Sargon has realized that they are not allowed to live in their world. He and Thalassa voluntarily leave their bodies after one last kiss in the bodies of their hosts and decide to live in the universe without using anybody’s body. Sister Chapel summarizes her experience: "The time with Spock was wonderful!" Spock looks emrassed.

Head picture courtesy of Ultimate Pix