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.On the first night of watch, Malcolm awakens to find Trelawny again on the floor, bloody and senseless. Margaret asks Dr. Winchester to summon another expert, and he calls for Dr. James Frere, a brain specialist. However, when Frere demands that Trelawny be moved from his room, Margaret refuses and sends him away. After a normal night with no attacks, a stranger arrives, begging to see Trelawny. He reveals himself to be Eugene Corbeck, an Egyptologist who was working with Trelawny. He has returned from Egypt with lamps that Trelawny requested, but finds upon his arrival at the house that the lamps have disappeared. The next day, Malcolm and Margaret admire Trelawny's Egyptian treasures, noting in particular a large sarcophagus, a coffer covered with hieroglyphics, and an oddly well-preserved mummy hand with seven fingers. Malcolm then finds the missing lamps in Margaret's bedroom. Concerned for Margaret, Malcolm tells Corbeck everything that has happened up until his arrival, and Corbeck gives Malcolm a mysterious book to read. The book tells the story of Nicholas van Huyn, a Dutch explorer who travelled to the Valley of the Sorcerer to explore the tomb of a mysterious Egyptian queen, Tera. In the tomb, he finds a sarcophagus and a mummy hand with seven fingers, adorned with a ruby ring with seven points that look like stars.Corbeck tells Malcolm that, years ago, he and Trelawny travelled to Egypt to search for the tomb where the sarcophagus lies. They find the tomb and discover that the mummy's wrist was coated with fresh dried blood. The hieroglyphics on the wall led Corbeck and Trelawny to believe that the mummy was possessed with some sort of black magic and that Queen Tera had immense power over the Upper and Lower Worlds. The hieroglyphics seemed to indicate that Tera planned to return from the dead. They took the sarcophagus from the tomb and left, only to be robbed of the mummy during a storm by their Arab guides. Trelawny suggested that they return to the tomb, where they found the mummy and the three Arabs, murdered. During their time in the tomb, they were put under some trance and recovered three days later to find that Trelawny's wife had died in childbirth, but Margaret survived. Sixteen years passed before Trelawny contacted Corbeck, frantic because he believed that the lamps they saw in the tomb, when arranged in a specific shape, would make the coffer open and would possibly be the key to Tera's resurrection.