S5, E4: After much deliberation, Dan decides to gather Serena, Blair, Nate, Chuck, Rufus and Lily to reveal the truth about his book in the hope that they will support him at his book party. Meanwhile, Blair and Louis (recurring guest star HUGO BECKER) enter crisis status after Louis reads Dan's book. Diana (recurring guest star ELIZABETH HURLEY) learns incriminating information about one of Nate's friends and uses it to her advantage.