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 remains -- 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...