On a stormy winter night, a strange, inexplicable murder occurs at Vainthorpe Castle. Young Henry Lavenham is stabbed to death outside the bedroom door of his young and beautiful stepmother. How did he end up there? Who killed him? Is it really the son of the owner of the castle, Robert Vainthorpe, who was found over a dead body with a dagger in his hand? Robert's sister, the abbess of the Tyndale monastery Elinor, who came to the castle to treat her sick nephew, and her companions must manage to find the real killer before the bad weather subsides and the sheriff can come for the suspect.