Kurt Ingston (Ralph Morgan) is a helpless cripple due to the incompetence of three doctors (Lionel Atwill, Frank Reicher, Francis Pierlot). He invites them to visit him at his estate on the pretext of donating money to medicine. One by one, the doctors are mysteriously murdered. The spooky mansion is filled with strange characters, any one of whom could be the killer. There is the ominous butler (Bela Lugosi), the grim housekeeper (Doris Lloyd), the lecherous chauffeur (Leif Erikson), a mystic (Nils Asther) and Ingston's demented sister (Fay Helm). Trying to solve the murders -- and stay alive -- are a psychiatrist (Irene Hervey) and a mystery writer (Don Porter).