Omar Roos, a maverick archaeologist, is disturbed by the death at the foot of the pyramids of Giza, of his old colleague, a famous Egyptologist, Richard Cranwell. Cranwell had become obsessed by his search for the legendary lost city of Zerzura. Ross's suspicions become further aroused by documents left referring to other deaths, of Carnarvon, of Wingate, of Carter, all linked by the inscription for the god Thoth. It seems as if Cranwell had been on the verge of a great discovery; but every contact, every informant, disappears: Cranwell's body itself is lost and Ross, threatened, beleagured and friendless, turns to his mother's family, of the Bedouin tribe.
