Things are not going well for Special Agent Pendergast. He's been locked up in a federal prison for a murder he did not commit. His friends, Lt. Vincent D'Agosta, Proctor, Pendergast's butler, and Constance Greene, Pendergast's ward, know who the real killer is: Diogenes, Pendergast's evil brother. The only way they can catch Diogenes is to break his wrongly accused brother out of prison.
At the New York Museum of Natural History, a generous benefactor has donated 10 million dollars to reopen the Tomb of Senef, an exhibit that has been closed since 1935 for unknown reasons. Dr. Nora Kelly is put in charge of restoring the exhibit and preparing it for a grand opening in only six weeks.
But strange things start happening at the museum. As the body count rises, D'Agosta and friends put their plan in motion, freeing Pendergast and putting him on a collision course with Diogenes' ultimate plan of revenge. But has his plan also put Diogenes in the crosshairs of someone else who wants to see him dead?