A wealthy and noble patron of one of the elite colleges in Cambridge hires John Holdsworth, the author of a popular book about ghosts, to conduct a private investigation. John must find out why her son Frank, a student at the same college, suddenly lost his mind. It is believed that the cause of insanity was a ghost that Frank saw in the university garden. Holdsworth admits the existence of evil spirits, however, once within the walls of Cambridge, he wonders whether the local ghosts are really to blame for Frank’s misfortune. His suspicions that there was some human involvement here grow stronger when John learns that there is a secret society in the college known as the Holy Spirit Club, and Frank was an active member of it...