3.11 "Treasure of Serena Madre"

As Thanksgiving draws near, Blair suspects her mother, Eleanor, has been keeping a big secret from her, but it turns out to be something else entirely. Meanwhile, Vanessa is supposed to spend Thanksgiving with her parents, but has a fight with her picky and estranged mother and she ends up going to Dan's loft. Rufus discovers that Lily has been lying to him about the true nature of her mother Cece's health. Chuck tells Nate that he has some potentially damaging information about one of their friends: Serena whom is caught in a compromising position with Trip Vanderbilt. Elsewhere, Jenny learns that Eric was behind her very public embarrassment at Cotillion and can't pass up a chance to get even with him in the most cruel way, which makes her appear even more vile and twisted than everyone else around her. Also, Serena is put in a very awkward position when Lily invites Trip and his wife, Maureen, to join them for Thanksgiving dinner at their penthouse, and Maureen may know a lot more about what is going on between Trip and Serena than she claims to, and Dorota is revealed to be hiding a secret of her own involving Vanya.