After Charles II reclaimed the throne in 1660, Oliver Cromwell's corpse was dug up, hanged, and beheaded as posthumous punishment for regicide. His head was spiked on a pole outside Westminster Hall, where it stayed for decades before beginning a strange afterlife as a private curiosity, passed between showmen, collectors, and society figures who displayed it, sold it, and argued over whether it was even genuine. This film traces that chain of custody through the eighteenth and nineteenth centuries, bringing in the eccentric owners who kept it in cabinets and drawing rooms, the forgeries that muddied the trail, and the forensic scientists who eventually examined the skull's wounds and skull structure to test its authenticity against portraits and death masks. Historians walk through the political calculation behind the original execution and desecration, and the detective work that finally established, as far as science allows, that the relic buried at Sidney Sussex College in 1960 really was Cromwell's. It is a grim, well-documented oddity of English history.