Gossip Girl Season 1 Episode 8

Blair is devastated by the current state of her relationship with Nate and the guilt from her recent indiscretion. But she manages to put on a happy face for her 17th birthday party and attempts to hide her feelings from her friends. Hoping to ease the tension between Serena and Vanessa, Dan takes Vanessa to Blair's party so the girls can bond together, but this ends up making Serena more uncomfortable.