After learning of mass murderer Jack the Ripper's gruesome reign of terror, private detective Sherlock Holmes (Christopher Plummer) decides to investigate. The police are no help, withholding information about the case from Holmes. But the detective refuses to be deterred, seeking the crucial assistance of psychic Robert Lees (Donald Sutherland), who sets him on the right path. Holmes, along with his trusted sidekick, Dr. Watson (James Mason), descends into a shadowy underworld of crime.