Adapted from a play written by two Monty Python vets, this toothy satire launches with a tragic accident at Chumley's chocolate factory when hapless manager Ian Littleton accidentally knocks several employees into a huge chocolate vat. The tragic mishap at the chocolate factory results in candy lovers getting an unexpected 'extra' in their sweets.
Dr Trevelyan calls on Holmes on behalf of his friend Blessington, after a Russian father and son vanish during a consultation. Blessington knows of no one who wishes him ill, but he is found hanged the next day. Holmes investigates, with advice from Watson.