January 1901. Abigail and Daniel Wilson, the celebrated 'Museum Detectives', journey to the Great Pyramid of Giza in search of ancient secrets. But their adventure takes a darker turn when, deep within the Robbers' Tunnel, they uncover a brutally murdered man - Simeon McGruder, an American writer who was investigating the mysteries of the Sphinx. Back in Cairo, the American Embassy draws them into the case, thrusting them into a web of intrigue. Caught between British and American powers, a fragile Egyptian government, and a circle of deceitful acquaintances, the Wilsons must navigate shifting loyalties and hidden motives, where every answer only deepens the mystery.