Bones: Season 4, Episode 21

4 - 21: Mayhem on a Cross

When a skeleton is found being used as a stage prop for a Black metal band in Norway, authorities call the FBI upon discovering that the man, a bassist with the stage name Mayhem, is a US citizen. The investigation into underground extreme metal bands brings to light the teams' own surprising musical preferences and new information about Sweets' past. Meanwhile, Dr. Gordon Wyatt is back, helping Sweets write his book on Booth and Brennan by giving him a perspective on their relationship.