While Miss Marple (Margaret Rutherford) and Mr Stringer (Stringer Davis) are soliciting donations for a charity ("The Reformed Criminals Assistance League"), they visit Mr. Enderby (Finlay Currie), a rich and eccentric recluse. He tumbles down the long entrance staircase, apparently the victim of a fatal heart attack. Knowing that Enderby had a pathological fear of cats, Miss Marple becomes suspicious when she finds one in the house. She also finds a piece of mud bearing the print of a riding boot, but when she goes to Inspector Craddock (Bud Tingwell), he is sceptical, believing that Enderby died of natural causes.