Joan and Sherlock attempt to catch Charles Augustus Milverton, a blackmailer who has been shaking down the families of rape victims, threatening to make videos of the assault public if they don't pay up. While discretely searching Milverton's house for clues, Sherlock and Joan witness a masked man break in and shoot the blackmailer dead. Unfortunately, Milverton had a fail-safe in place – an accomplice tasked with making all of the blackmail material public should anything ever happen to him. If Sherlock and Joan want to prevent the sexual assault videos from going public online, they'll have to figure out who the accomplice is before he gets wind of Milverton's untimely death. Meanwhile, Alfredo attempts to get Sherlock to celebrate his first full year of sobriety with an AA chip, something Holmes is against.