The original Gossip Girl cast returns in a reimagination of their high school days in which Blair and Vanessa become unlikely roommates! Blair and Serena were BFFs ...until Blair discovered that her boyfriend, Nate, cheated on her with Serena! As if that wasn't enough, Serena then disappeared without a word. Now she's back and trying to make amends with Blair. Too bad Serena's former best friend has no intention of forgiving her. After seeing Serena with her new boyfriend, Dan, Blair intends to respond in kind! Will a photo of Dan kissing Blair put an end to Serena's budding relationship ...?