Sherlock sends Joan off to a hotel while he entertains one of his sexual partners, a British climatologist named Agatha. Sherlock and Joan are soon called to the scene of a murder, where a Zooss driver was murdered, apparently by a cabbie. Sherlock finds clues that lead them to discover that the death wasn't about cabs at all. When they track down the killer, they discover that the killer was actually blackmailed into murder.

The victim, besides being a driver, also worked as an online journalist with dreams of being an investigative reporter. They learn that he was having an affair with his boss, who was also being blackmailed. Sherlock realizes that both blackmail victims are connected by Zooss, and that the victim Galen was trying to uncover the blackmailer's identity.

Sherlock and Joan learn that there was a Zooss programmer who was killed, but Sherlock soon deduces that he wasn't killed because he'd discoverd the blackmail scheme, because he was the blackmailer. He was killed for an unrelated reason. It isn't long before Sherlock realizes that the one who started it all was another Zooss employee, who was using the company's application to stalk a woman. He arranged the murder of Galen when Galen got too close to discovering the truth.

Meanwhile, Sherlock deals with an unusual request from Agatha to donate sperm to impregnate her as part of a plan by his father to continue the Holmes family line. Sherlock ultimately refuses because he does not want to share the pain of his superior senses of the world on another human being.