Kate Killigrew had left New York City, her advertising job, and her ex-fiance to come to the small island off the North Carolina coast. Her first night in the old house she has rented, she looks out of her bedroom window and sees a girl, clad in what might be a summery caftan, gazing at the house in the chill moonlight.

The next day a man appears on that same stretch of beach. His name, he says, is Martin Donnerly, and he and his wife once lived in the old house. Strongly attracted to him, Kate wonders if he is still married and, if not, what became of his wife.

The islanders are eager to tell Kate how Martin had killed Donna Sue, his lovely, promiscuous wife, with a blast from his double-barreled shotgun. Now he was paroled after serving twelve years of his sentence. Martin claims that he was innocent, but no one would believe him. Falling deeply in love, Kate knows their only hope for a future together is to find the real killer. But whom should she suspect? The lustful police chief? The banker's chic daughter, obviously infatuated with Martin? Martin's rich, snobbish brother? Or one of Donna Sue's backwoods kinfolk--her sly and violent brothers or her beautiful twin sister, brain damaged at birth, who roamed the countryside like a stray cat?

It is not until her own life hangs by a thread that Kate discovers the killer. And it is not until then that she feels she knows for certain who it was that she saw standing in the cold moonlight that first night on the island.