Plot summary
After a run-in with an increasingly paranoid Bart, Blair grows concerned for Chuck's safety. Feeling confident that his father will never hurt him, Chuck makes a deal that could change his life. Blair devises a plan with the help of Serena, Georgina, Sage, and Ivy to get what they need out of Bart. Meanwhile, Nate's financial dilemma lands him in a place that he never thought he would be: jail. In the end, Chuck is escorted by Bart's security to the roof of a building. Minutes later Bart joins him.
Blair, alarmed at not being able to locate Chuck, asks around for him and races up to the roof as well. A fight ensues between Chuck and Bart. Blair arrives just in time to see Bart hanging off the side of the building. Chuck refuses to help him up for fear that he would harm his friends or himself. The episode ends with Bart falling and Blair and Chuck running off. Title reference: The 2012 film The Avengers.
Credits
Adapted from Wikipedia contributors, Gossip Girl season 6. HTML formatting and reference markers removed.