<P> Unable to withstand not meddling, Blair follows Eva selling the watch that Chuck gave her and hatches a scheme to expose her as a gold digger . Blair tries to expose her but fails when Eva explains that she was selling the watch to pay the mortgage of Chuck's valet, displaying her altruistic personality and making Chuck have Eva decide to which charity he will donate to . Dan and Serena's conversation moves towards having fun instead of facing his loss . Blair calls on Serena's aid to uncover dirt regarding Eva's past and Serena recruits Dan to help her . Eva slowly reveals her past to Blair but finds nothing worthy of ruining her . Nate later sees that Juliet has been lying about her whereabouts and is determined to find the truth . Returning to her apartment, Dan and Serena explain that Eva was a prostitute . Blair kicks out Dan and finds Serena reluctant to see him go, not only finding dirt that she could use to ruin Eva but the revelation that Serena chose Dan when she intended to make a choice after Paris . Blair encourages Serena to attend Chuck's party and look for Dan . </P> <P> At the party, Blair finds out that Chuck is already aware of Eva's past and shrugs off Blair's attempt, Dan and Serena meet but are disturbed by Vanessa, who confronts Dan over his avoiding his loss over Milo and reveals that Serena was making a choice between him and Nate, and Nate confronts Juliet over her lying about her whereabouts . Chuck makes his announcement, stating that he will be setting up a new charity, one that Eva will be heading . Making a last - ditch effort to ruin Eva, Blair takes Chuck's passport from his valet in Eva's luggage to frame her for gold - digging and succeeds . Chuck asks Eva to leave but discovers from Lily that his passport was with her . Realizing his mistake, Chuck pleads with Eva to stay, even mentioning "everyone leaves me ." However, Eva, heartbroken, still leaves because, after all the love and kindness she has showed him, he still doubted her sincerity and believed Blair . When Nate turns to Serena, a jealous Dan confronts her stating that he knows about her decision between him and Nate, leaving Serena upset . Juliet then reveals that her brother is in jail and Nate gladly accepts her apology and her invitation into her apartment . </P> <P> The closing montage shows Dan opening his heart regarding Milo and his love for Vanessa, and Juliet paying a concierge for pretending that she owns her expensive apartment and fooling Nate . Chuck, believing that Blair wanted only to hurt him, goes to Blair's apartment and declares war on her for making Eva, the only good thing to come into his life, leave . He reveals that he's returned to his worst self and fires his valet . Blair and Serena, in the closing seconds, comfort each other . </P> <P> This episode marks Katie Cassidy's fourth episode in the series and the final appearance of Clémence Poésy as Eva Coupeau . A scene involving Eva and Blair was filmed at an Adopt - a-Pet in Queens . Blake Lively and Penn Badgley filmed a scene at Central Park . </P>

What episode does chuck and eva break up