Folge 8.

We meet the great villains who've battled with TV's greatest detective. There's Jim Moriarty, his nemesis. There's Charles Augustus Magnussen, the only man Sherlock Holmes truly hates. And then there's Mycroft Holmes - Sherlock's brother and the last word in sibling rivalry. All of them have had influence over those closest to Sherlock. And all of them cause him grief.