Complete story — includes the ending
Mycroft is being framed as the mole, so Sherlock relocates him and Joan to a vacant, remote library accessible only to Sherlock. The three identity Sherrington as the mole, but decide to keep it quiet. Sherrington eventually visits Joan at the brownstone to confront her, but Joan had invited members of "Everyone" to a video chat to have witnesses for protection. Sherrington leaves. He had made seventeen calls to his contact Afkhami, who is spying for the Iranian government. Sherlock and Joan investigate a murder believed to be linked to Afkhami. He deduces that the victim was stoned to death. Afkhami's wife was having an affair, so he killed her lover. Sherrington betrayed MI6 because of a lack of promotion or respect due, he believes, to his working-class background. The NYPD later finds Sherrington's corpse. Mycroft made a deal with the NSA for them to kill Sherrington and fake Mycroft's own death to protect Joan and the brothers from Le Milieu. Mycroft embraces Sherlock and says that he loves him. While Joan makes plans to move into a new apartment, Sherlock accepts MI6's invitation to join them.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, List of Elementary episodes. HTML formatting and reference markers removed. · Content license