A composer (Laurence Payne) is stuck in a middle-class marriage and finds that his affair with his wife's half-sister (Jane Griffiths) has resulted in a pregnancy. When his wife refuses to give him a divorce he hatches a murder scheme that is too clever by half.

A group of scientists are kidnapped and taken to an outer space outpost in order to save Earth from destruction.

When his wife stops writing to him and his letters are returned unanswered, Dan becomes extremely concerned about her welfare. He returns home but is only able to meet with her briefly before she is found murdered. Dan is the obvious suspect but has only 36 hours to find out who murdered her. In so doing he uncovers a shocking catalogue of his wife's past affairs and an identity that he knew nothing about.