S4, E20: Blair's dreams appear to be coming true, but Serena threatens to jeopardize it all by dredging up Blair's past. Charlie (recurring guest star KAYLEE DeFER) befriends Vanessa, who may or may not have a hidden agenda. Nate is torn between his relationship with Raina (recurring guest star TIKA SUMPTER) and a truth he must keep hidden out of loyalty to Chuck.