Chuck's Last Chance
Although Chuck has sworn not to interfere with the wedding (and given Father Cavalia food poisoning so that he can't ruin it, either) he finally gets a sign he can't ignore. Eleanor herself shows up at Chuck's penthouse and says she won't let Blair make the same mistake that she once did by walking down the aisle toward someone she doesn't love. She begs him to break up the wedding and he agrees to talk to Blair.
Chuck asks Blair to go away with him, but she catches him off guard and admits that even if she weren't with Louis, she wouldn't be with him, either. After she leaves to start the ceremony, Georgina steps in with a video camera and tells Chuck that she caught the entire conversation on tape before tossing him the evidence.