Bridget Kelly (Sarah Michelle Gellar) is a recovering drug addict and stripper in Wyoming. She is under the protection of FBI Agent Victor Machado (Nestor Carbonell), having agreed to testify against her employer, local crime boss Bodaway Macawi (Zahn McClarnon), whom she witnessed committing murder. Fearing that Macawi, who has already murdered several witnesses linking him to previous crimes, will also kill her, Bridget flees to New York to meet her estranged twin sister Siobhan (also played by Gellar).
Soon after Bridget's arrival in New York, Siobhan, who had kept her sister's existence secret from her family, appears to commit suicide by jumping into the ocean. Bridget then assumes Siobhan's identity and tries to fit in among Siobhan's wealthy social circle, including Siobhan's husband Andrew (Ioan Gruffudd), stepdaughter Juliet (Zoey Deutch), best friend Gemma (Tara Summers), and Gemma's husband Henry (Kristoffer Polaha) with whom Siobhan had been having an affair. The only one who knows that Bridget is passing as Siobhan is Bridget's Narcotics Anonymous sponsor Malcolm (Mike Colter). Bridget's life becomes more complicated as she discovers that her sister was hiding secrets of her own and that someone is trying to kill Siobhan as well. ~Wikipedia