Tempe's work at the Jeffersonian Institute is put on hold when Special Agent Seeley Booth, stalled on a case deposing a Chicago mob family, calls her in to assist with a bizarre discovery: a plastic bag of skeletal remainsmdash;and a chilling note—left on the steps of a federal building. Tempe determines the bones are from different corpses, suggesting a serial killer's handiwork. A suspect is quickly taken into custody, but Tempe senses the case is far from closed. And as Booth's Mafia case heats up with violent twists and bloody discoveries, including ties to one of Chicago's most gruesome and notorious killers, Tempe must unravel the story of the bones, where the truth lies buried—in order to stay alive.