Serena (Blake Lively) and Dan (Penn Badgley) realize that they need to make amends with the people they have wronged. Blair (Leighton Meester) has one last chance to prove to her mother her worth as a fashion designer and with Serena's help, comes up with a plan to make her line the "it" look for Sage (guest star Sofia Black-D'Elia) and her friends. Chuck (Ed Westwick) is close to getting the evidence he needs against his father, until one of his closest allies reveals his plan to Bart (guest star Robert John Burke).