Malcolm Ross, a young barrister, is awakened in the middle of the night and summoned to the house of famous Egyptologist Abel Trelawny at the request of Abel's daughter, Margaret, of whom Malcolm is enamoured. Once Malcolm arrives at the house, he meets Margaret, Superintendent Dolan, and Doctor Winchester, and learns why he has been called: Margaret, hearing strange noises from her father's bedroom, woke to find him unconscious and bloodied on the floor of his room, under some sort of trance. Margaret reveals that her father had left a letter of strange instructions in the event of his incapacitation, stating that his body should not be removed from his room and must be watched at all times until he wakes up. The room is filled with Egyptian relics, and Malcolm notices that the "mummy smell" has an effect on those in the room. A large mummy cat in the room disturbs Margaret's cat, Silvio, and the doctor suspects Silvio is guilty of the scratch marks on Trelawny's arm.