"Turnabout Intruder" is the twenty-fourth and final episode of the third season of the American science fiction television series Star Trek. Written by Arthur H. Singer (based on a story by Gene Roddenberry) and directed by Herb Wallerstein, it was first broadcast on June 3, 1969. In the episode, a woman switches bodies with Captain Kirk and then tries to take over command of the Enterprise. Originally scheduled to air at 10pm on Friday, March 28, 1969, NBC pre-empted it with a special report on former U.S. President Dwight D. Eisenhower, who had died earlier that day. On June 3, 1969, after an absence of two months, Star Trek was brought back on a new night and time: Tuesdays at 7:30pm. "Turnabout Intruder" was the only first-run episode to be shown in this new time slot. This was the last original episode of Star Trek to air on NBC. Plot The Federation starship Enterprise answers a distress call from the planet Camus II, the site of an archaeological expedition. Among the survivors are Dr. Janice Lester, with whom Captain Kirk was once intimately involved, and the expedition's physician, Dr. Arthur Coleman. Coleman claims that Lester is suffering from radiation exposure. Dr. Coleman, Science Officer Spock and Chief Medical Officer Dr. McCoy leave to tend to the other survivors, leaving Lester and Kirk alone. The two reminisce about the time they spent together at Starfleet Academy and her lingering resentment at her inability to rise to captain due, she implies, to Starfleet's prohibiting female captains. Kirk explores the room, and as he examines an alien machine, she activates it, paralyzing him. She then joins Kirk in the machine and activates it again. From each of their bodies a ghostly image emerges and then disappears into the other's body. The person appearing to be Kirk then declares that Janice Lester has taken the place of Captain Kirk, and begins to strangle the person appearing to be Lester. Spock and McCoy return before “Kirk” can finish the job, and he orders the landing party and the remaining survivors back to the Enterprise. Once there, he gives Dr. Coleman full authority for treatment of “Janice Lester”, over McCoy's protests. Alone, Coleman and “Kirk” discuss the situation. It is revealed that the two conspired to kill the expedition's personnel. Lester has now achieved her lifelong goal of commanding a starship. Spock becomes suspicious when “Kirk”