In the midst of Fashion Week, a furious Blair learns that her mother, Eleanor, at the suggestion of her protege Jenny, has given Serena and her new socialite friend, Poppy Lifton, front row seats to the Eleanor Waldorf show. Hurt once again by Serena's popularity and her mother's betrayal, Blair decides to sabotage the show. Meanwhile, Dan starts hanging out with Chuck, but a walk on the dark side always has its risks and Dan learns that the hard way. Lily learns a secret that her new husband, Bart, has been keeping from her.

Chuck, Sarah and Casey try to retrieve a vital component for the new Intersect: The Cipher.

At the Buy More, the search for the store's Assistant Manager begins.

Chuck and Sarah go on their first date.

Casey is again instructed to eliminate Chuck as soon as the new Intersect comes online.

Seeing Penny with another guy sends Leonard back to Leslie Winkle, much to Sheldon's dismay.

Cameron has a software glitch and loses her memory, causing her to leave the Connors. She is taken in by a homeless kid named Jody, who ends up at a halfway house with her. Meanwhile, Agent Ellison meets with Catherine Weaver to talk about his future with Zeira Corp.

With Ted McGinley and Jeffrey Ross gone from the show, the 11 remaining dancers perform once again in week 2 of the competition tackling the paso doble or rumba!

Marshall claims that he had the best hamburger in the world during his first week in New York City, but he forgot where the burger joint is located. The gang then hits the streets of Manhattan to help him find it.

HRG and his new partner go to a local bank heist with four villains; including Peter being trapped in one of them. Hiro and Ando track Daphne to Germany, and meet the Haitian. Tracy Strauss goes to New Orleans to find out more information about Nikki. Meredith teaches Claire a lesson about fighting. Usutu shows Matt a series of paintings about him.

Tree Hill is in an uproar as Nanny Carrie has finally gotten Haley where she wants her - unfortunately, that means both Haley and Jamie's lives are in danger. Peyton feels threatened when Lucas must reunite with Lindsay for a business meeting. Meanwhile, Brooke's struggle for control at Clothes Over Bros reaches the breaking point as Victoria continues to exert her power by making unexpected and unsettling business decisions.

The entire operation may be in jeopardy when Mahone gets into trouble with the law. Gretchen's sister receives a surprise visitor. The Company may be onto Self. T-Bag continues to raise suspicions at Gate.

Alan goes too far in effort to collect $38 he loaned to Charlie. Evelyn arranges a job for Jake.

Three American soldiers plunge into the Niagara River and swim to Canada. Deserters, refusing to return to Iraq under the U.S'.s "stop loss"? policy, they seek refugee status in Canada. Major Mike Kessler and his Immigration and Customs Security (ICS) Squad are forced to deal with the fallout - from Canadian anti-war protestors to an incensed American four-star general. One of the soldiers has a psychotic breakdown forcing Major Kessler to face his worst nightmare.

Sam tries to win over Dick by charming Angela, but then ruins any progress he made when he has a mishap with Dick's birds.

When Denny faints in the lobby of Crane, Poole & Schmidt, Alan helps him take on the drug companies that contributed to his critical condition.



Meanwhile, Carl helps Shirley's granddaughter Marlena who once again finds herself in legal trouble after voting in the presidential primaries, and Jerry and Katie defend a young girl who was raped in a private prison.

The residents of Miami are killing each other after gas prices skyrocket and the CSI team encounters Miami's most brutal crime ring yet.

Doug and Stephanie have to explain themselves to Lauren. Meanwhile Heidi's mother pays a visit.

We meet John Armstrong, a man who works at a stationary store with greeting cards, is suspected of murdering people by putting people in trunks and letting them suffocate. Also, an ice cream truck driver sells more than ice cream from his truck.

Jerry takes on an emotional case of the murder of a young boy. As the press coverage intensifies, Balco takes over as lead prosecutor. Bobbi defends a family man charged with possession of heroin. Jerry finally meets Bobbi's husband and they continue to flirt.

to be announced...

Tonight Stephen welcomes political commentator and author of Third Term: Why George W. Bush (Hearts) John McCain, Paul Begala.

Rachel faces up to her shameful past. In flashbacks, she tells how she met, fell in love and eventually left Daniel, the man responsible for emailing their private video.

When the TR team intercepts a known drug dealer, they discover that a robbery is about to take place, which then turns into a siege when the robbers take hostages. One of the criminals falls into a basement beneath the bar and later dies. Dom goes in to try to convince the robbers to stop, but the owner of the bar is shot by a spear gun. Eventually, one of the criminals gives up while the other is arrested.