Executive producer: Gene Roddenberry
Associate producers: Edward K. Milkis and Gregg Peters
Producer Fred Freiberger
Co-producer: Robert H. Justman
Story consultant: Arthur H. Singer

Writers: Judy Burns and Chet Richards
Dir.: Ralph Semensky

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 Chapel: Majel Barret
Lt. O'Neil: Sean Morgan

Stardate 5693.4

The Enterprise, in search for the U. S. S. Defiant, approaches her drifting, close to the place the ship sent her last signal. Spock wonders about the data in his computer: The space seems to fall apart. Suddenly Chekov finds an object in front of them and Spock can't confirm what all they see: The instruments do not show the object. Kirk, Spock, McCoy and Chekov don space suits and beam over end find all crew of the Defiant dead, having killed each other. The captain's neck is broken and Spock checks the computer: There is no life on board. Sulu cannot make out the definite situation of the Defiant and feels as is she is drifting away. Chekov gives his report: All dead –all have killed each other. 

Spock finds the same readings he had found on board of the Enterprise. Kirk understands: Whatever happened here might also happen on his ship. Spock agrees. Drifting on, the ship approaches a parallel dimension and all must hurry to get back before the ship dissolves. Her instability effects the Enterprise, too. Scotty has only energy for three to beam back at a time. Spock wishes to stay behind to "get some more readings", but he has to obey his captain's decision: McCoy, Spock and Chekov go first. Then the Defiant dissolves totally.

Kirk does not make it back with the others. Spock and Scotty try their best, but do not find any substance in her place. His computer tells Spock that the next materialization phase will be in 4 hours and 6 minutes. Chekov is beginning to build up tension. While Spock is answering his question whether he had meant that there are several universes existing beside each other at the same time, he becomes tense and suddenly attacks the others, shouting: "We all will die!" In sick bay a medical assistant suddenly attacks Dr. McCoy, who only can react in time because Nurse Chapel comes in the moment the man is trying to kill the doctor and promptly sedates him. 

McCoy asks Spock whether he has any hope to get the captain back – alive and Spock explains that he was caught in the transmitter beam, which might have saved him. They are interrupted by Sulu – a ship is approaching. The Tholian Commander advises the Enterprise to leave the area. In command of the ship, Mr. Spock asks for permission to stay as long as the rescue mission lasts = 113 minutes. During the next materialization phase the captain does not appear in the transmitter and McCoy urges Spock to leave the area, because the aggression occurs according to changes in space as they experience them now. 

Without having captain Kirk back and now the Tholians firing at the Enterprise Spock remarks: "The Tholians are remarkably in time." They keep on firing and Spock orders all power on the defense shields. Again Spock orders to make contact with the Tholians, without any response. As the Tholians keep on hitting the ship with phaser beams, he orders power on the phasers, too. "There is no use to fight a battle after the captain is lost," McCoy confronts him. Spock looking at him steadily dryly asks: "Ready, Mr. Sulu?" McCoy confronts Spock: No experienced captain would have jeopardized the crew that way. Spock comments calmly that he does not find these comparisons helpful in the moment. 

The phaser beam stops the attacks of the Tholian ship. A second ship appears and they begin to spread an energy web around the Enterprise which now cannot maneuver. Spock calls the representatives of the various sections for a meeting. He informs them that it was the captain's wish to remain behind in order to save the lives of the three of them. After the fight with the Tholians, he tells them, the captain might be dead or drifting in space. The meeting is interrupted by a crew member experiencing an outburst like the others had. After his speech doctor McCoy reminds Spock that there is a record they should watch in case the captain is dead. Spock still wants to wait before watching it -he still hopes to find his captain, but does not share it with McCoy. He tells him that he is needed on the bridge. But McCoy insists, it was Jim's wish. 

McCoy accuses Spock of not having saved the Enterprise and Spock confirms that he had to try to save the captain as long as he thought it was possible to do so. Both listen to the tape. Kirk gives an advice to Spock on his tape, knowing they hear it only when they think he is dead and Spock has taken over the Enterprise. He shares his admiration for Spock's talents and knowledge. And he advises him to listen to his emotions, he thinks he has. In case he has misjudged him, he advises his friend to go to McCoy to seak for emotional advice, because leading a ship needs both: Logic and listening to one's feelings. Kirk orders McCoy to always respect Spock's decision and to be loyal to him as he was to himself. After the disc is over McCoy says: "Spock, I am sorry. It was pretty tough, wasn't it?" "What do you like to hear from me, doctor?" ... 

They are interrupted by the intercom. Scotty has calculated when the Tholians will have finished the web, which is closing them in. In her private room Mrs. Uhura sees the captain and so does Scotty in the machine room. Spock thinks it might be that people see what they wish to see. McCoy worries about the disease spreading all over and Spock wants to order him back to the laboratory to work on fighting the disease. Suddenly McCyo becomes angry. Very calmly Spock waits and McCoy realizes he has chosen the wrong tone. He apologizes, but Spock assures him that there is nothing to excuse. Suddenly all of them see the captain on the bridge – half materialized, semi transparent. And he vanishes again. Spock knows the next materialization phase will be stable -in about 20 minutes. 

McCoy enters Spock's rooms with an antidote to the disease while the Vulcan and Mr. Scott are talking about the energy resources of the ship. McCoy declares that it is a Klingon poison dissolved in distilled water + alcohol; it only tranquilizes some nerves. Scotty says: "That you could have achieved with a good scotch, too. Does it go together with a scotch?" 
"Yes," McCoy says, "it should." "I'll try that," Scotty leaves. "You, too, have to drink it, Spock, and if only to give a good example." McCoy toast towards Spock: "I order you to drink it in my position as doctor of the ship, captain!" Both toast to each other. 

Back on the bridge Spock greets Mrs. Uhura: "Good to see you back on the bridge." Which Mrs. Uhura gladly acknowledges. Spock also remarks to Chekov: "We have missed you very much." "Thank you, Mr. Spock!" The time of the next materialization comes closer: 10 seconds and the captain appears again, Scotty still announces only 80% of power. Using the overlapping of the dimensions they escape through the other dimension out of the Tholian web, the captain in the transmitter beam. 

Out of the net with full power regained they transmit the captain on board of the Enterprise, his oxygen resources nearly empty. Back in his commanding chair Kirk asks how both of them came along together. Both agree to have managed fine. Then Kirk wants to know what they think of his record. "What record?" both wonder. "The speech I gave to you," Kirk reminds them. Neither McCoy nor Spock can remember having watched it – there had been no time for that, they agree.