Adam Hart, investigator of the occult, and his faithful companion Victor Janis, are contacted by a young woman, Myra. She’s worried there’s something wrong with Robert, the man she’s just married. She explains that since the day he overcame his fear of heights - to save her from falling off a bridge in front of a train - he’s behaved strangely, for instance appearing in the streets while claiming to be at home. Myra, afraid that Robert will kill her, asks Adam and Victor to accompany her and Robert on their honeymoon to the Sahara Desert. They agree. On the ship bound for Tripoli, Adam and Victor meet a doctor, with whom Adam fiercely debates the existence of the supernatural. The doctor refuses any such nonsense, but Adam baffles him with his great knowledge and razor-sharp wit. Meanwhile, an unseen stranger attacks Robert, throwing him overboard. But just as the ship’s crew is trying to retrieve him, Robert shows up on deck, having apparently somehow managed to climb back onboard. Adam however notices that part of his trousers are dry! In Tripoli, Myra decides that all is well with Robert, and the happy honeymooners drive off into the desert. But while sightseeing in Tripoli, Adam suddenly solves the mystery, realizing that both Myra and Robert are in greater danger than ever. Using a landrover, Adam, Victor and the doctor race into the desert where a terrible sight awaits them: An unlocking of occult forces so undeniable, that even the doctor’s stout worldview will be severely challenged.