"What kind of a boat do you think this is?" said the eunuch indignantly when Captain Owen came aboard. Well, what sort of boat was it? After all, a young woman had drowned in the Nile, her body washed up on a sandbar. Apparently she had fallen off this boat.

Owen, as Mamur Zapt, or head of British-ruled Cairo's secret police, deems it a potential crime. But when the poor girl's body suddenly vanishes from its resting place, he must investigate a crime that is as substantial as the Sphinx...and every bit as mystifying.

Strange, he muses, that the girl would have plummeted off a boat when it was moored for the night in a river that was calm. What is even stranger is that the boat was in the hire of Prince Narouz, son of the Khedive, the nominal ruler of Egypt. Why had the prince commanded the dahabeeyab to cruise to Luxor in the first place? Certainly, he had no interest at all in antiquities. And what was an attractive and unwed young woman doing aboard the vessel after dark?

Owen must mount a puzzling search for the truth that will take him from Cairo's sophisticated French-style cafes to the darkest recesses of its dingiest slums. Helped by his frightfully independent Egyptian mistress and a remarkable assortment of informants, he soon finds himself adrift in the seething waters of Edwardian Egyptian politics.