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

Story by: Gene Roddenberry
Writer: Arthur A. Singer
Dir.: Herb Wallerstein


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
Dr. Janice Lester: Sandra Smith
Dr. Arthur Coleman :Harry Landers
Communication officer Angela: Barbara Baldavin

Stardate 5298.5

Camus II. Two scientists, Dr. Janice Lester and Dr. Coleman, call the Enterprise because Dr. Lester is ill. She had been involved with Kirk, once, and is now working on Camus II. While she is alone with Kirk, Dr. Lester sedates him for a moment, long enough to attach him to a machine which switches the souls, the personalities, between two people. Both attached to the machine, she becomes the captain (outwardly) and Kirk becomes her. In the captain's body, she puts her body (Kirk) on her bed and, as Spock, McCoy and Dr. Coleman join them, states that Dr. Leslie has not been awake since he was in. 

On board Dr. Coleman, obviously cooperating with her, keeps Dr. Lester sedated. On the bridge the crew notices a change in behavior at once. Spock wonders about a course correction noticing that "the captain" has forgotten about a meeting with another starship. When Spock repeatedly tries to change the course again, in order to reach a station where the best medical treatment for Dr. Lester (as he thinks) is possible and which is on the way to the Enterprise's original destination, "Kirk" becomes irritated and even rude towards him. Spock must also remind him that such a change of course requires personal notification of starfleet by the captain himself. 

Though Dr. Lester had prepared herself for months for that occasion to lead a starship, "he" leaves the bridge angrily. Some provocative and aggressive actions of "the captain" make people wonder about his state of mind. McCoy insists in an examination. While McCoy, Spock and Kirk are in sickbay, Dr. Lester rushes in. She has freed herself and now asks Spock and Bones to help her, saying she is Kirk and Kirk is Dr. Lester. The captain knocks her down and orders her to be brought back to sickbay with guards allowing only him to visit her. Spock follows immediately and tries to see her. The guards first do not want to allow him in. As Spock asks whether this order applies to a leading officer, too, one guard agrees but insists to go in with him. 

Do these orders concern a leading officer?

Dr. Lester, very much self controlled in comparison to the captain, calmly explains to Spock about the machine on Camus II, which switches personalities and bodies. Spock finds it interesting and wants proof. She suggests the mindmeld. Now Spock is convinced and simply says: "I believe you." Taking her out of sickbay the guard opposes him. "Yes, we all have to do our duty," Spock says and softly touches his neck. Before fainting the guard calls out. As the other guard enters, he, too, is sedated by the neckpinch. McCoy has ascertained out that the captain is healthy – though he too wonders about the change in behavior. The moment both leave sickbay, Kirk and McCoy approach the room. 

Spock clearly states that he believes Dr. Lester and that he will do anything to keep the captain from staying in command. Kirk turns around and publicly accuses Spock of mutiny via intercom and orders his arrest. Drawing their phasers on Spock the guards arrest him. A hearing is held right away. Trying to avoid it at first Kirk shows different behavior than Kirk ever did, while Spock calmly insists in maintaining his opinion. Dr. Lester is questioned as well and shows the routine behavior of Kirk. Again Spock insists that the thruth must be found and the captain Kirk can't command the Enterprise – having the mindmeld as the only proof to mention. 

During a break McCoy and Scotty are overheard as they confirm each other in their believe in Mr. Spock. Back in the courtroom their conversation is played back to all crew members and both are accused for mutiny too – by the captain. Kirk orders Spock's, McCoy's and Scotty death for mutiny. Sulu and Chekov oppose, but in vain, the captain uses the rules his way. On the bridge Sulu and Chekov refuse to follow orders again. Nobody can believe the captain has ordered the death sentence for his three friends. For a moment the captain becomes weak. He changes for a second into Dr. Lester, becomes himself again. 

In the prison cell Dr. Lester feels for a moment like having been on the bridge. Spock confirms: It might be possible that the effect faints by the time. Kirk hurries to Dr. Coleman asking how the exchange back into their natural bodies can be prevented. Only by death of Kirk, Coleman says. "Kirk" orders him to execute the death sentence and he first refuses. But he/she talks him into doing it. Opening the force - field of the prison cell, Dr. Coleman takes Dr. Lester out. He wants to inject her the deadly fluid and she fights him. The others leave the cell and witness how the exchange back between Dr. Lester and captain Kirk takes place in this moment. This time it stays permanently. Her dreams shattnered Dr. Leslie gets a fit and hits Dr. Coleman in agony. Calmly captain Kirk asks Dr. Coleman whether Dr. Leslie can be helped and Dr. Coleman expresses his wish to care for her. Kirk, Spock, McCoy and Scotty leave for other work ahead.