Serena, Blair, Nate, Chuck and their entourage break into the school swimming pool for a night of fun, but when a member of their group nearly drowns, the school threatens to expel the person responsible for the break-in. Everyone agrees to keep a secret pact and say nothing, but when Dan tells Serena he doesn't want to take the fall for someone else, Serena confides that she's the one responsible. Serena ultimately confesses, and isn't expelled. Vanessa is working on a documentary project about private schools and accidentally captures Blair and Chuck discussing their affair. Lily contemplates turning down Bart Bass's proposal to give things with Rufus another shot, but Serena begs her not to make her and Dan step-siblings.