S5, E24: In the fifth season finale, when Gossip Girl goes after Blair as never before, Serena admits she may have unintentionally played an important role in Blair's latest nightmare. Meanwhile, Nate invites Lola (recurring guest star ELLA RAE PECK) to move in with him, and Lily must make a big decision about the future of her marriage. Finally, by episode's end, Blair will make a choice between the two men in her life … will it be Chuck or will it be Dan?