Archaeologists around the world are anticipating a sensation: a perfectly preserved Egyptian mummy, called Lady X, was found in the storerooms of one of the Boston museums. A specially invited forensic expert, Maura Isles, is present during the tomography of the find. Imagine the surprise of Maura and the other participants in the experiment when they discover... a bullet in the leg of the ancient exhibit! As it turns out, Lady X is not two thousand years old... Soon, detective Jane Rizzoli finds several more frightening artifacts in the museum basements, and it becomes clear that the mummified victims are the work of a killer with special knowledge and skills. The Death Keeper is the seventh novel in an episode dedicated to Jane Rizzoli and Maura Isles.