Season: Two — Episode: 24 Director: John Polson — Writer: Robert Doherty & Craig Sweeny — Aired: May 15, 2014 — Viewers (millions): 7.37 Summary: Rising tension between Sherlock and Watson bring their partnership to a crossroads, but they endeavor to put their differences aside while they help Sherlock's brother, Mycroft, who faces accusations of treason and murder.
You have this kind of pull. Like gravity. I'm so lucky that I fell into your orbit.
— Watson to Holmes
After bursting in on Mycroft and Watson, Sherlock explains that Mycroft is being framed for murder and that the gun used to kill MI6 asset Arthur West turned up with Mycroft's fingerprints on it. Disbelieving, Mycroft thinks Sherlock is making an excuse to interrupt him and Watson until Sherlock activates the remote starter on Mycroft's car which explodes. At a safe house, Sherlock believes a mole in MI6 is framing Mycroft. He's told MI6 what he knows but also said that Mycroft is the mole. He hopes this will gain MI6's confidence and while pretending to work with them to find Mycroft, that he'll find the real mole. Sherlock meets MI6 Deputy Chief, Sir James Walter and Mycroft's handler, Tim Sherrington, but is unsuccessful in gaining access to their files. He lies that he'll let them know when he finds Mycroft. At the safe house, Mycroft expresses regret for re-joining MI6 and indicates he did it to gain favor with his father and Sherlock.
Would you like to see what else the mole has in store?
Watson joins Sherlock on a stake-out of the bookstore of Julian Afkhami, who West believed was an Iranian spy. Holmes tells her that MI6 won't work with him and that he found a transmitter in the bookstore's phone junction box that West might have planted. Once Afkhami leaves, they break into his store and Sherlock finds a scrambler that Afkhami could use for certain calls. West wouldn't have understood the calls but Sherlock believes he would know the date, time and location of them. At the safe house, Sherlock examines the info West had tattooed on his arms. Although burner phones would have been used by Afkhami's contact, the code of the cell tower used would be part of the metadata of the call. Sherlock realizes this is what West tattooed on his arms. As he reads the locations and dates, Mycroft confirms that he was at locations. Watson deduces that Sherrington was also there and that he is the mole.
A game of cat and mouse is afoot.
Mycroft protests that Sherrington brought Sherlock onto the investigation which indicates that he did so at his superior's request, Sir Walter. At The Brownstone, Sherrington calls Sherlock for a progress report. Sherlock lies that Mycroft accessed funds from one of his father's charities which he is using to find him. Watson offers to help Sherlock look at the dates Sherrington called Afkhami but he insists on working alone since Watson announced that she'll be moving out of the Brownstone. The next morning, Watson wakes to find a trail of flashcards bearing the dates tattooed on West's arms and a significant event that happened on the date. Sherlock has found that the dates correspond to events that benefited Iran and that Sherrington provided secret information to make the events occur. He's discovered the events on all dates but one, March 5. Captain Gregson then calls him to the 11th Precinct.
Looks like you had a productive night.
At the precinct, Gregson and Detective Bell tell Sherlock that they have the gun used to kill West and that Mycroft's fingerprints were found on it. They ask his location but Sherlock feints ignorance and says Mycroft is not the killer. At the Brownstone, Sherrington drops by to speak to Watson. She makes him wait outside and then leads him to the media room. He asks for insights as to Mycroft's location and when she provides a different lead than Sherlock did, Sherrington threatens to torture her. Watson activates the monitors which each shows a different member of Everyone who have been listening. Sherrington vows to deal with her and the Holmes brothers and leaves. Watson calls Sherlock who returns concerned, both for Watson and that Sherrington now knows they are on to him. However, Watson has discovered the missing event that occurred on March 5.
An Iranian, Nadir Khadem, was beaten to death in NYC which a blogger claimed was a political killing. Watson is enthusiastic as, all the other events happened outside the US but this event is local and can be investigated. However, Sherlock is distracted by Watson's near miss with Sherrington and is angry that Mycroft's involvement with MI6 has affected their lives. Watson tells him that the reason Mycroft re-joined MI6 was to save him from imprisonment.