January 1901. Abigail and Daniel Wilson, often lauded as 'The Museum Detectives', are on their way to the Great Pyramid at Giza. Their explorations, including the Robbers' Tunnel, take a very sinister turn when they come upon the body of a man who has been brutally murdered. Investigations by the local police reveal him to be Simeon McGruder, an American writer who was penning an article about the mysteries of the Sphinx. When Daniel and Abigail return to Cairo they are asked by the American Embassy if they can take on the case, but they have a difficult path to tread as they try to keep different factions onside: the British and American authorities, the puppet Egyptian Government and officials, while at the same time facing lies and deviousness from McGruder's associates and friends.