On the run from the mob, Bridget assumes the identity of her deceased twin sister, Siobhan, only to realize that her sister's life was no less complicated than hers.

Bridget scrambles to find a way to cover up a crime she recently committed, while still leading everyone to believe that she is Siobhan Martin. Bridget's past starts to catch up with her, however, when FBI Agent Machado decides to stay in New York City and investigate Siobhan's life.

Bridget discovers a possible clue that could lead to Siobhan's hugger, and uncovers intriguing information about Andrew. In other events, Machado continues to pursue Bridget; and Henry and Gemma butt heads over their investment in Andrew's hedge fund.

Bridget, who's still posing as Siobhan, heads to the Hamptons with Andrew, Gemma and Henry to celebrate Siobhan's birthday. While there, Henry is adamant about rekindling his affair with Siobhan. In other events, Gemma learns some unsettling news; and Bridget is forced to reveal some of her past when Machado closes in on some new information.

Gemma asks Bridget, who is still posing as Siobhan, to do her a risky favor. Henry receives some disappointing news about his writing career, and Andrew struggles with his rocky relationship with his teenage daughter, Juliet. Bridget meets a potential new sponsor named Charlie at a local Narcotics Anonymous meeting, while Malcolm battles his demons when he is put in a situation that threatens his sobriety.

Bridget can't connect with Gemma, causing her to wonder if something occurred between Gemma and Henry; Juliet's teacher comes to her aid when she stands up to a bully at her new school; Bridget asks Charlie for a favor; Machado investigates Malcolm's disappearance.

Siobhan-Bridget reveals that she has a twin to Andrew and Henry; Henry becomes a suspect in the disappearance of Gemma; Juliet parties to dangerous extremes; Malcolm escapes.

Andrew and Bridget learn some unsettling news that also affects Henry. Juliet continues to grow slower to her teacher, Mr. Carpenter, and Malcolm arrives in New York, where he is confronted by Agent Machado. Siobhan\'s relationship with Tyler is jeopardized.

While Henry and Olivia form an attraction to each other, Bridget\'s realizes she\'s developed feelings for Andrew. Bridget\'s new NA sponsor raises concerns with Malcolm. Hoping to find out more about Siobhan, Bridget sets up an appointment with her sister\'s therapist.

Henry homes in on a suspect in Gemma's disappearance; Malcolm goes to the police with his hunch about Charlie; Juliet becomes obsessed with Mr. Carpenter; Machado meets with an informant (Amber Benson) in Wyoming.

Bridget offers to host a fund-raiser for Juliet's school and learns that her friend Greer knows one of Siobhan's secrets; Siobhan can't believe that Bridget has adapted as well as she has to her new life; Malcolm goes to work for Andrew; Henry mourns his wife.

Juliet's mother visits and causes trouble for Andrew and Bridget; Bridget discovers someone she believes is key to learning more about her sister; Henry finds a lead that causes Machado to think he's closing in on Bridget.

Bridget retraces Siobhan's last steps prior to her disappearance and discovers that her twin kept a secret office; Olivia blackmails Henry into introducing her to Gemma's wealthy father; Tyler faces a moral decision that could impact Siobhan and Andrew.

Bridget encounters someone who played an important role in her and Siobhan's past; Malcolm discovers something of Bridget's in Henry's possession; Catherine asks Andrew to make a decision about Juliet that could have major ramifications.

Bridget realizes she's in over her head when Andrew proposes again; Olivia becomes suspicious of Malcolm; and Juliet makes a decision that doesn't sit well with her mother.

Machado's past with stripper Shaylene Briggs is revealed; Siobhan masquerades as Bridget to Malcolm; Henry realizes that Bridget knows more than she should; and Tyler takes something from Siobhan that's a key piece of evidence in her revenge plot.

Bridget fears that something has happened to Malcolm when she cannot get in touch with him.. In an effort to find him, Bridget visits the hotel where Malcolm was staying and discover on security footage that Andrew was the last person to see Malcolm before he disappeared. Meanwhile, Juliet discovers that someone in her family played a part in the attack on Tessa and Siobhan admits to Henry the reason she faked her passing.

After an attempt is made on Bridget's life, Agent Machado is determined to find who was responsible. Henry accuses Siobhan of putting a hit out on Bridget, while Bridget thinks Olivia was behind it. Meanwhile, Andrew admits to asking Malcolm to leave town and Juliet goes missing.

Bridget decides to testify against Bodaway Macawi; Machado is suspended from the FBI; and Henry gives Siobhan an ultimatum: give up the revenge plot or they're through.

Bridget, as Siobhan, tells Machado about the attempt on her life and who she suspects was behind it; Bridget accuses Henry of Tyler's cuddle unaware that Siobhan is listening in; and a desperate Catherine takes extreme measures to get closer to Andrew.

Catherine's plot to drive apart Andrew and Bridget falters; Machado learns who wanted Siobhan dead; and Siobhan's plan to help Henry hits a snag.

As the vow renewal nears, Bridget realizes she first needs to tell Andrew the truth about who she really is. Meanwhile, just as Bodaway Macawi starts to close in on Bridget, Agent Machado is forced off the case and Henry decides whether he should tell Bridget the truth about Siobhan.