Serena, Blair, Chuck and his new girlfriend head back to New York on the September 27 new episode of Gossip Girl, and Serena and Blair come to blows (again).  We've already posted promo photos for the upcoming episode and now the CW has released a trailer and a sneak peek, which we have for you below.

BACK TO THE UPPER EAST SIDE!

On her first day at Columbia, Blair (Leighton Meester) attempts to gain membership into an ultra-exclusive social club, Hamilton House, but she’s in for a few big surprises. Serena (Blake Lively) begins to suspect that Juliet (guest star Katie Cassidy) is intentionally sabotaging Serena’s life and that it may have something to do with Nate (Chace Crawford).

Rufus (Matthew Settle) is worried about Dan (Penn Badgley) and decides to take matters into his own hands. Ed Westwick, Jessica Szohr and Kelly Rutherford also star.