July, 1955. Donald Langham has interrupted his romantic break in rural Suffolk with the delectable Maria Dupre to assist a fellow writer. Alastair Endicott has requested Langham's help in discovering what's happened to his father, Edward, who seems to have disappeared without trace from inside his locked study. Before he vanished, the elder Endicott had been researching a book on the notorious Satanist Vivian Stafford. Could the proposed biography have something to do with his disappearance? Does local resident Stafford really possess supernatural powers, as some believe?