Jon Snow and the rest of the Night's Watch face the biggest challenge to the Wall yet as the Wildlings attack Castle Black from both sides. Ahead of the battle, Maester Aemon reveals that he is secretly a Targaryen who could once have been King of Westeros, and Gilly and Little Sam, having escaped Mole's Town, arrive at Castle Black, where Sam hides them. Tormund's army breaks through from the south and engages the Night's Watch, while the Wildlings climbing the Wall are obliterated by a massive swinging scythe trap. Pyp is killed by an arrow from Ygritte, and a giant breaches the tunnel into Castle Black but is killed by Grenn and five others at the cost of their own lives.
Alliser Thorne is wounded in a duel with Tormund and forced to withdraw, leaving Jon to take charge of the defense. After seeing Jon kill Styr, Ygritte aims her bow at him but hesitates, then is fatally shot by Olly, dying in Jon's arms. Assisted by Jon's direwolf, Ghost, the Night's Watch secures Castle Black's inner keep, and a wounded Tormund is captured. As the Wildlings retreat for the night, Jon goes beyond the Wall on a suicide mission to find and kill Mance Rayder, believing the Wildling army will fragment without his command.