FBI Special Agent Aloysius Pendergast is faced with a frightening fact: one of his friends, journalist Bill Smithback, has been murdered in his own apartment by his housemate, who has been dead for ten days! This seems impossible, but the testimony of witnesses is irrefutable. The case smacks of mysticism, especially since certain objects were left at the crime scene, clearly associated with some kind of cult. Pendergast learns that shortly before his death, Smithback was collecting materials about a strange sect involved in animal sacrifices...