<P> Serena has a breakdown and eventually confesses to Blair, Nate and Chuck . It is revealed that after Serena had sex with Nate at a wedding, Serena went to join Georgina and a boy named Pete Fairman at a hotel, who hid a video camera in the room to tape him and Serena having sex . Serena wasn't in the mood, though, and instead passed Pete a line of cocaine which he subsequently overdosed on . Panicked Serena called the emergency services and she and Georgina fled the hotel . After learning that Pete had died Serena ran away to boarding school . </P> <P> It is learned that Chuck lost his virginity to Georgina in the 6th grade and he remembers her partying attitude before Serena went to boarding school . Serena tells them that Georgina is blackmailing her into continuing the lifestyle they used to have . </P> <P> At Rufus's concert, Dan and Vanessa learn that Sarah is in fact Georgina . Vanessa is told the truth by Nate but Georgina successfully deceives Dan by concocting a story about an abusive ex-boyfriend . In light of Dan and Serena's break - up over her constant lies to cover - up her secrets, Georgina tells Dan that she is falling in love with him, she then phones Serena on Dan's phone and tells her "all bets are off" implying she'll be having sex with him that night . </P> <P> The next morning Serena confronts Georgina at Dan's apartment and furiously tries to attack her . After Georgina leaves Serena eventually tells Dan the truth which he believes and with the help of Blair, Dan devises a plan to get rid of Georgina . Dan calls Georgina up and has her meet him in Central Park; he consequently leaves her after she confesses her feelings for him and is met by Blair who has tracked down Georgina's parents . Blair reveals that Georgina was supposed to be at an equestrian circuit but sold her show pony for cocaine . Georgina was in fact in a rehabilitation center in Utah where she escaped, hitchhiked into a town, stole a credit card and booked a ticket to Ibiza . Georgina is left with her parents who decide her fate by sending her to a boot camp for troubled young girls, upon Blair's suggestion . </P>

When does dan find out the truth about georgina
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