Bran's Fall

While climbing the broken tower at Winterfell, Bran Stark stumbles upon Queen Cersei and Jaime Lannister engaged in incestuous intercourse. Jaime pushes Bran from the window to silence him, leaving him in a coma with a broken back. Bran's direwolf, Summer, howls in distress. This event is a turning point, crippling Bran and setting the Stark-Lannister conflict in motion. It also reveals the secret of Cersei and Jaime's relationship, which becomes a central mystery.