Casting 1.3 - The great game

This episode doesn't lack of excellent characters ! I made a subjective choice with the list below :

1.3 - The great game

Mycroft ask for his brother's help (sort of) in dealing with an affair of national interest.
While Sherlock affects to refuse, a bomb explodes in Baker street. That's the beginning of a game which will lead to a crucial meeting between Sherlock and his biggest fan...