When several women are murdered and their forefingers severed, Holmes and Watson are called into action, but Holmes is baffled by the crimes at the start. Widower Sir George Fenwick (Paul Cavanagh), after a romantic night at the apartment of Lydia Marlowe (Hillary Brooke), is hypnotized into believing that he is responsible for the crimes. He is certain that he is guilty after he awakes from a stupor and finds a woman's forefinger in his pocket. His daughter comes to Holmes and Watson without realizing that Moriarty's henchman is following her. She tells Holmes and Watson that she found her father burying a forefinger under a pile of soil. She has dug up the forefinger and shows it to them.