MONDAY, SEPTEMBER 15

"GOSSIP GIRL" � (8:00-9:00 p.m. ET)

"The Dark Night" (TV-14, DL) (HDTV)

CHUCK LOSES HIS MOJO � Serena (Blake Lively) and Dan (Penn Badgley) are forced to deal with their unspoken problems while trapped in an elevator during a citywide blackout. In a humorous twist, Blair (Leighton Meester) questions the lack of passion in her relationship with Marcus (guest star Patrick Heusinger), while at the same time Chuck (Ed Westwick) appears to have lost his "passion" for any woman other than Blair. Meanwhile, Nate (Chace Crawford) struggles between his feelings for Vanessa (Jessica Szohr) and his more-complicated-by-the-day relationship with Catherine (guest star Madchen Amick). Jenny (Taylor Momsen) risks losing her internship when Eleanor (Margaret Colin) catches Jenny critiquing one of the Eleanor Waldorf designs. Matthew Settle also stars. Janice Cooke directed the episode written by John Stephens (#203).