GONE MAYBE GONE

Blair and Chuck make a deal that involves putting their whole relationship on the line. Meanwhile, Dan returns from Italy after deciding to write a revealing book about the Upper East Side's scandals with Georgina's help. Nate is determined to take Gossip Girl down for good by trying to find her real identity. Also, the gang comes together to look for a missing Serena, but the search ends with surprising results. (Gossip Girl Wiki)