The film opens in Edinburgh. Narration by Angus the Hangman explains how the corpses of the hanged are transported to Dr Robert Knox for dissection. Knox's rival, Dr Alexander Monro (tertius), wants the steady supply of cadavers but is forced to rely on severed limbs for dissection. Monro's assistant Charles Darwin arrives with a letter containing a bylaw directing that all corpses thenceforth must be sent to Monro. Angus tells Knox's assistant, Patterson, the news. Patterson delivers the message to Knox.