In answering a medical emergency at an archaeological expedition, Kirk confronts the deep hatred of an old love, Janice Lester, who supposedly lies severely ill from celebium radiation. In payment for jilting her back at Starfleet Academy, Dr. Lester arranges for an alien machine to swap her consciousness with that of the captain and takes command of the Enterprise. Once aboard, Kirk (in Lester's body) tries to convince Spock that he is trapped in her body. As a result, Janice (in Kirk's body) conducts a court-marshal with the intent of executing Spock and Kirk (in Janice's body), and later McCoy and Scott, to keep her secret. The crew realize something is seriously wrong with their captain and, not wishing to incur an illegal death-penalty themselves, begin a passive resistance. Written by
Did You Know?
Nurse Chapel's (Majel Barrett
) hair color is brown for this episode, not its usual blonde color. See more
When Spock and McCoy are conversing in sickbay, McCoy is wearing his medical garb. However, in the first couple of close-ups, his shirt changes to his regular uniform. See more
Dr. Janice Lester
[in the body of Captain Kirk, narrating
James Kirk is returning to consciousness in the body of Janice Lester. The Enterprise is proceeding to its next mission, on the course set for it before I took over command. Now the years I spent studying every single detail of the ship's operation will be tested. With a little experience, I will be invulnerable to suspicion. At last I attained what is my just due - command of a starship. All the months of preparation now come to fruition