It was the first of Koontz's novels to appear on the New York Times Best Seller list, and is widely credited with launching his career as a best-selling author.

Hilary Thomas, a screenwriter living in Los Angeles, is attacked in her home by Bruno Frye, a mentally disturbed man whose vineyard in Napa Valley she recently visited.

Detective Tony Clemenza tells her that Frye has an airtight alibi, as the police called his home and he answered, proving that he could not have been anywhere near Los Angeles that night.

Hilary and Tony meet a retired madam who tells them that Leo, Frye's grandfather, brought his daughter, Katherine, there to be cared for after he got her pregnant.

Directed by Douglas Jackson, the film starred Victoria Tennant as Hilary, Chris Sarandon as Tony, and Jean LeClerc as Bruno.