Confusion rages in the Stormlands in the wake of a devastating reversal: Renly is killed by Melisandre's shadowy assassin, and excluding the Tyrells, his forces join Stannis. Brienne, accused of the murder, must flee with Catelyn and swears lifelong fealty to her for saving her life. At Harrenhal, Jaqen H'ghar, a Faceless Assassin and one of three caged prisoners Arya previously saved from a fire, pledges to kill any three people she chooses to repay his debt; her first choice is the Tickler, the man who tortures the captives to death. Theon, seeking to prove himself a true Ironborn, sails from Pyke and, against Yara's orders, intends to capture Winterfell during Robb's absence.
Lancel tells Tyrion about wildfire, a mass-produced explosive hidden in the city's dungeons and intended to destroy Stannis's fleet and army during the impending siege, and Tyrion takes control of the scheme. In the north, the Night's Watch arrives at an ancient fortress called the Fist of the First Men, and Mormont hands command of Jon over to the legendary ranger Qhorin Halfhand, who is leading a team into the Frostfang mountains to spy on the gathering wildling host. In Qarth, Xaro proposes marriage to Daenerys in exchange for the wealth to conquer the Seven Kingdoms, but Ser Jorah convinces her to instead gain the support of the Westerosi people.