Terrorism shakes the foundations of the Navy and NCIS to such an extent that Gibbs and the team face surprises that will devastate them.
Blair must make the big choice between Dan or Chuck; Lola reflects on Nate asking her to move in with him; Lily makes a final decision regarding her marriage.
William van der Woodsen returns to the Upper East Side to deal with a family emergency, while Blair fears Cyrus has found a loophole somewhere in her prenup. Also, Georginia and Chuck band together with a mischievous plot, leading to an unpredictable finish.moreless
Famed improv troupe, The Upright Citizen's Brigade, selects excerpts from Dan's book to perform. Blair endeavors to save her friendship with Serena by trying to prove her suspicions aren't true.
Lily, Charlie and Serena anticipate a party thrown in CeCe's honor. Nate takes on a new role at the Spectator, and his first big job is of someone he knows very well. Meanwhile, Blair turns to an unlikely source for help.moreless
Nate has to decide whether to cross moral lines at Diana's request. Dan is trying to figure out who is publishing his book, and seeks help to stop it but ends up in the spotlight anyway. Chuck helps Dan and Dan helps Chuck break through. Meanwhile, Serena and Charlie return to the Upper East Side.moreless
In the season four finale, will Blair choose her prince or her dark night?
The finale includes the return of Georgina and Constance Billard mean girls Kati and Is, a cameo by "Gossip Girl" author Cecily von Ziegesar, a performance by Airborne Toxic Event and, oh yeah, a few very juicy cliffhangers.