Marty Maxwell, a wealthy, but unhappily single tycoon decides to marry one of his four ex-wives and invites the women to a party to get reacquainted. He also invites Mike Shayne to the party, telling him that he has evidence that one of the women wishes to kill him. When Maxwell, as a practical joke, pretends to be poisoned, Shayne storms out of his apartment, but wishes he had stayed when he learns that his former client had, in fact, been murdered later in the evening.