A mysterious skeleton buried in a shallow grave beneath a famous ancient monument. Who was he? How long had he been there? And why had his head been severed from its body? Archaeologist Mike Pitts works with scientists, forensics experts and historian to dig up ominous information about early Britain and the circumstances that surrounded the man's death. Was he a cattle thief, an insurgent, or a pagan sacrifice in a newly Christian world? (UK/PBS 55 min)