Lily, Charlie and Serena eagerly anticipate the Studio 54 party being thrown in CeCe's honor. Nate takes on a new role at the Spectator, but his first big story turns out to be about someone he knows all too well.

Blair thinks Cyrus may have found a potential loophole in her prenup. Chuck and Georgina partner up in a scheme, but it has an unpredictable outcome. Meanwhile, a family crisis brings William van der Woodsen back to the Upper East Side.

Chuck invites Jack (DESMOND HARRINGTON) to town, Blair and Dan attempt to consummate their new relationship and Ivy finds an unlikely ally in William (BILLY BALDWIN).

Serena tries to make a reluctant Lola the next It Girl of the Upper East Side, starting with modeling at a Kiki de Montparnasse show.

Chuck, Nate, Blair, Serena and Lola team up to uncover what they think is an explosive secret between Diana and Jack. Meanwhile, Dan is offered a prestigious fellowship in Rome for the summer.

Serena poses as Blair at an important meeting. Ivy and Lola (ELLA RAE PECK) team up to help Chuck. Nate makes a decision about the future and Diana (ELIZABETH HURLEY).