Bridget Kelly is six-months sober and starting to turn her life around when she is the sole witness in a murder trial. Despite the assurances of her FBI protector, Agent Victor Machado, Bridget knows her life is on the line. She flees to New York, telling no one, and reunites with her estranged twin, Siobhan Martin. Wealthy, pampered and married to the strikingly handsome Andrew Martin, Siobhan lives what appears to be a fairy tale life - a life where no one knows that Bridget exists. The sisters seem to be mending their frayed relationship - until Siobhan disappears ...
Bridget struggles to figure out a way to cover up a crime she has just committed, while still convincing everyone she's Siobhan Martin. Her old life begins to catch up with her, as FBI Agent Machado decides to stay in New York and learn more about Siobhan's life and inner circle. As Bridget falls further into a web of lies, she confides her secrets to Malcolm, which risks putting him in danger. Andrew and his business partner Olivia throw a party to obtain new clients, which puts a wrench in Bridget's plans, while Gemma and Henry's fighting escalates as Gemma ...
Bridget learns she has a potential clue to bring her closer to Siobhan's killer. Bridget discovers some interesting information about Andrew, which causes tension between them. Meanwhile, Agent Machado continues his pursuit of Bridget and tensions flare between Henry and Gemma over their investment in Andrew's hedge fund.
Still posing as Siobhan, Bridget, and Andrew head to the Hamptons with Gemma and Henry to celebrate her birthday. Despite the close quarters, Henry is dead-set on rekindling his affair with Siobhan. Gemma learns some unsettling news, while FBI agent Victor Machado closes in on some new information, which forces Bridget to reveal some of her past in order to protect her secrets.
Gemma reacts angrily to Bridget's revelation, and threatens to expose Bridget unless she exposes Henry's infidelity. Things get worse from there. Bridget goes to an Narcotics Anonymous meeting and does not give her name. "Siobhan" apologizes to Juliet for "stealing" her dad from her mom, and they begin to reconcile.
When Bridget cannot get in touch with Gemma she begins to wonder if something has happened between Gemma and Henry. Juliet starts a new school, where she defends herself against the school bully and her teacher Mr. Carpenter comes to her rescue. Bridget asks Charlie to do her a favor that could come back to haunt her, while Agent Machado looks into Malcolm's disappearance.
Still posing as Siobhan, Bridget is forced to reveal she has a twin to Andrew and Henry when Agent Machado starts closing in. Henry becomes a suspect in the whereabouts of his wife, Gemma and Juliet starts partying to dangerous extremes. Meanwhile, Malcolm escapes and is on the run from his kidnappers.
Andrew and Bridget are told some upsetting news that also affects Henry. Juliet continues to form an unlikely bond with her teacher Mr. Carpenter and Malcolm shows up in New York, where Agent Machado confronts him. Meanwhile, Siobhan's relationship with Tyler is jeopardized.
Bridget begins to realize she is developing feelings for Andrew, while Henry and Andrew's business partner Olivia bond over common interests. Malcolm is suspicious of Bridget's new NA sponsor Charlie and Bridget makes an appointment with Siobhan's therapist, hoping it will help her discover some insight into her sister's life.
Henry begins to target someone as a suspect in the disappearance of his wife Gemma and realizes he must work with Bridget to find out more information. Malcolm talks to the police about his suspicion of Charlie, while Juliet develops an unhealthy obsession with her teacher Mr. Carpenter. Meanwhile, Agent Machado meets with an informant back in Wyoming.