An archaeological site among the ruins of a dead civilisation, where Dr Janice Lester uses an alien device to exchange bodies with Captain Kirk in Turnabout Intruder.
Camus II is a planet bearing the remains of a long-vanished culture. It appears in Turnabout Intruder, the final episode of the original series.
The Enterprise answers a distress call from a scientific expedition there. Nearly all its members are dead from celebium radiation. The survivors are its leader Janice Lester, apparently gravely ill, and her physician Arthur Coleman. Lester, who was once close to Kirk at Starfleet Academy, has in fact sent her own staff to their deaths.
Among the ruins she has found a machine able to transfer one mind into another body. Alone with Kirk, she traps him against it and takes his body, leaving him in hers. She then assumes command of the Enterprise until the transfer weakens and reverses.