Episode 2-5
Title: "The Ghost of Harrenhal"
Directed by David Petrarca
Written by David Benioff & D. B. Weiss
Original Air Date -- April 29, 2012
In Harrenhal, Arya Stark is promised help by the mysterious Jaqen H’ghar, one of the three caged prisoners during her trip to the Wall. After Renly's sudden death at the hands of Melisandre's shadowy assassin, Catelyn and Brienne are forced to flee from Renly's camp. Theon sails from Pyke prepared to prove that he is a true Ironborn, with plans to overtake Winterfell while Robb is out fighting the war. The Night's Watch arrive at an ancient fortress called the Fist of the First Men, where they intend to make a stand.
Source:
https://en.wikipedia.org/wiki/Game_of_Thrones_(season_2)