Dr. Janice Lester switches bodies with Captain Kirk

The Constitution-class Federation starship USS Enterprise NCC-1701, under the command of Captain James T. Kirk, arrived at the planet Camus II, responding to a distress signal from an expedition there. The leader of the expedition was Dr. Janice Lester, an old flame of Kirk's from his days at Starfleet Academy. Lester has come to despise the captain because he was able to achieve what she never could--command of a starship. When Captain Kirk and Dr. McCoy beamed down, they found out that most of Lester's party had passed away and Lester herself seemed to be on the verge of death. But Kirk learned, too late, that Lester apparently had faked her illness--and killed her own staff--to lure Kirk into a trap. Lester had discovered an alien device capable of swapping minds between two individuals. Before Kirk could figure out what was going on, she knocked him out and transferred her mind into his body and his mind into hers. At long last, Lester would be captain of the Enterprise. But, in order to hold on to this hard-won victory, she needed to take care of one final detail--kill Kirk.