Sherlock and John investigate the mystery of Sherlock's missing sibling, and the trail leads to Sherringford.
Sherlock is drawn into the case of Culverton Smith after the man's daughter claims that he wiped her memory after confessing that he was a serial killer. Meanwhile, both Sherlock and John deal with their grief in the aftermath of Mary's death.moreless
While waiting for Moriarty to make good on his threat from beyond the grave, Sherlock distracts himself with cases. He stumbles upon one that he believes is connected to his nemesis.
Martha represents a man accused of raping his ex-girlfriend, and has to put aside her own feelings for the man in order to win the case. Meanwhile, Niamh is given an opportunity to claim a cheap court victory. Will she take it?moreless