Cordelia Gray inherits the detective agency she works for, after the death of her boss. Her first case is when she is hired by Ronald Callender, an eminent scientist, to investigate why his son, Cambridge University student Mark Callender, has committed suicide. She soon discovers the case is more dnagerous and complex than it at first appeared. She moves into the summer house where he was found hanged, and finds herself threatened. The investigation ends in nightmarish fashion.
