10/20/2008 AT 12:00 AM EDT
In Monday's episode of Gossip Girl
, steely Vanessa uses a compromising picture of Marcus and Catherine to blackmail Blair into helping her with a charity of her choice. But Blair says, "Charity is for diseases and endangered species," and she's not going to be convinced otherwise. Of course, she might need help from a certain someone who is willing and able to play dirty. So, she sends Chuck on a mission: "seduce and destroy."
Watch two more clips below.