Sherlock is called to prison when Moran (M) reveals that he will reveal information about more past murders, but only to Holmes. Instead, the killer tells Sherlock that Philip Van Der Waal, a man recently found dead from a heart attack, was on his list of intended victims from Moriarty. Find the man who killed Van Der Wall, M tells Sherlock, and heâ��ll lead you right to Moriarty. With this information, Sherlock and Joan are able to track down and capture The Actuary, a soft-spoken assassin in Moriarty's employ. Of course, this only deepens the mystery of what Sherlock's greatest nemesis actually wants.