Jessie Markham has a split personality - first she is an assassin, shooting a businessman in the men's room of a restaurant, then after falling asleep she wakes as a nervous wife, remembering her actions only as a nightmare. Her husband is very solicitious, perhaps because of the wrist scars that mark a suicide attempt after a brutal rape. But in her next episode of the assassin 'dream', she meets a man she is instantly attracted to: her husband. Who is the real Jessie Markham? And which is the real life that she is leading? Is she the wealthy heiress on an island honeymoon who gradually suspects this husband of plotting her murder? Or is she the ravishingly, cold-blooded assassin-for-hire who preys exclusively on men?.. Each seems to exist only in the dreams of the other. And neither knows which of them is real and which is a nighttime hallucination.