Just before stubborn millionaire Edwina Cutwater dies, she asks her uptight lawyer, Roger Cobb, to amend her will so that her soul will pass to the young, vibrant Terry Hoskins – but the spiritual transference goes awry. Edwina enters Roger's body instead, forcing him to battle Edwina for control of his own being.

A crew of interplanetary archaeologists is threatened when an alien creature impregnates one of their members, causing her to turn homicidal and murder them one by one.