After Eleanor gives Blair an ultimatum, Blair is even more determined to remedy Waldorf Designs� problems by making a splash with a dress at the upcoming Cotillion, but a shocking revelation at the ball affects everyone. Serena becomes worried about Steven�s attitude toward her, but after some investigating she discovers the surprising reason why. Chuck finds an unlikely ally as he tries to drive a wedge between Bart and Lily�s relationship to help expose his father�s secret. Meanwhile, Dan publishes another article, but the effect is just the opposite of what he was hoping for.