In 1849 American society was shaken by the grisly news that a prominent and wealthy Bostonian, George Parkman, had been killed and dismembered. The subsequent trial found a Harvard medical professor, John White Webster, guilty of murder, and he was sentenced to death by hanging. Historian Simon Schama investigates the case in the light of ongoing doubts about Webster's guilt, and attempts to solve the celebrated murder mystery once and for all.