The finale to the New York Times bestselling Secret Series!A class trip to the local natural history museum turns dangerous when Cass accidentally breaks a finger off a priceless mummy. This "crime" of vandalism leads her and her friends Max-Earnest and Yo-Yoji on an expedition into a land of majestic pyramids, dusty tombs, and the walking dead. Is it Egypt? Or somewhere much stranger... . . . . . . . . .