A few months after the end of World War II, Miles Hammond is invited to the first meeting of the Murder Club in five years. When he arrives, no one else is there except Barbara Morell and Professor Rigaud. When no one else shows up, Rigaud tells the story of Fay Seton.
Seton was a young girl, working for the Brookes family. She fell in love with Harry Brookes, and the two became engaged. But Harry's father, Howard, did not approve. One day, he agreed to meet Fay in a tower—all that remained of a burned-out chateau. It was a secure location on a lonely waterfront, and was the perfect place for such a meeting. Harry and Professor Rigaud left Howard alone at ten minutes before four. When they returned, fifteen minutes later, Howard had been stabbed, and the sword-cane that did it was found in two pieces beside his body. At first it seemed an open-and-shut case, but a family that was picnicking a few feet from the entrance of the tower swore that no one entered the tower in those fifteen minutes, that no boat came near the tower, and no one could have climbed up, because the nearest window was fifteen feet off the ground. The only one with any motive was Fay Seton, who was believed to be able to bring a vampire to life and terrorize people.
Miles quickly becomes involved in the affair because the new librarian he just hired is Fay Seton.