“GOSSIP GIRL” — (9:00-10:00 p.m. ET)
“The Undergraduates” (TV-14, L sptv050769) (HDTV)

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. Norman Buckley directed the episode written by Amanda Lasher (#403).