23. Art in the Blood

Complete story — includes the ending

Sherlock returns home to find Joan safe. Mycroft is actually working for MI6. MI6 utilized Mycroft's observational skills to investigate criminal groups such as Le Milieu. Mycroft's handler, Tim Sherrington, wanted Sherlock out of New York. Sherrington hires Sherlock to investigate the murder of Arthur West, an MI6 analyst. West's arms were stolen from the morgue. West's estranged wife, Marion is a tattoo artist; she tattooed West's arms with information using invisible ink. West was confident that there was a mole within MI6, communicating with bookstore owner Julian Afkhami. Sherrington eventually offers Sherlock a job at MI6. Marion, meanwhile, tells Joan about one "Sudomo Han". Mycroft had left MI6, but rejoined in exchange for Sherlock's freedom. While he was a drug addict in Britain, Sherlock had worked for Han as a courier, unaware that the latter was a terrorist. Joan and Mycroft eventually have sex. Elsewhere, Sherlock learns that the gun used to kill West bore fingerprints bearing a distinctive scar. He identifies the fingerprints as Mycroft's.