Harlee covers up the murder of her abusive ex, while Wozniak makes a deal with FBI Agent Stahl to stay out of jail.

Following Wozniak's (Ray Liotta) discovery that Stahl's (Warren Kole) target is his close friend and Mayoral Candidate, Julia Ayers (guest star Anna Gunn), Wozniak launches an all out war with Stahl. Meanwhile, Harlee (Jennifer Lopez) dives into an investigation that takes an unexpected turn into her own past and ultimately throws her in the cross hairs of Wozniak and the FBI. At the precinct, a new, unwelcome presence threatens to uncover the crew's deepest secrets.

After Wozniak (Ray Liotta) refuses to play ball with the FBI, Stahl (Warren Kole) turns up the heat on Harlee (Jennifer Lopez) who lands in the middle of Wozniak's dangerous plan to free himself from the Feds by reeling in a bigger fish. Meanwhile, Internal Affairs Officer Verco (guest star Dov Davidoff) applies pressure to each member of the crew to discover what really happened to Donnie Pomp.

Realizing that Stahl (Warren Kole) will stop at nothing to arrest Julia Ayres (guest star Anna Gunn), Harlee (Jennifer Lopez) decides to investigate on her own and determine whether there's any truth in his allegations of Ayers' active business with the mob. Wozniak (Ray Liotta) is confronted with a drug case that forces him to face the darkest demons from his past, his daughter's death, while exposing the origin of his loyalty to Ayres.

The mafia seeks revenge on Harlee (Jennifer Lopez) by framing her for murder. As Harlee works against the clock and her own crew to cover her tracks, Wozniak (Ray Liotta) fights to keep his cop family together when evidence of an old crime puts pressure on the already splintering team. Stahl (Warren Kole) cozies up to Cristina (Sarah Jeffery), getting one step closer to the truth about Miguel.

Harlee (Jennifer Lopez) and Wozniak (Ray Liotta) investigate Caroline's (Nava's ex fiancée) murder, putting Harlee and Nava's (Gino Anthony Pesi) relationship in an awkward place because she can't reveal her connection to the crime or the methods she will use to solve it. Wozniak focuses on determining which member of his crew is informing to Verco (guest star Dov Davidoff) as Loman (Dayo Okeniyi) uncovers a much deeper secret.

Following Harlee's (Jennifer Lopez) brave confession to the entire crew that she has been informing for the FBI, the team grapples with Harlee and Wozniak's (Ray Liotta) betrayal. With their team falling apart, Harlee and Wozniak come up with a desperate plan to neutralize Bianchi (guest star Ritchie Coster). However, their actions have unforeseen consequences because the Mafia fires back.

Wozniak (Ray Liotta) goes after Bianchi (guest star Ritchie Coster) for breaking their agreement. Harlee (Jennifer Lopez) seizes the opportunity to unite the team around an illegal mission to repay Tufo's (Hampton Fluker) brother's debt to a local drug dealer. Stahl (Warren Kole) heightens the stakes making good on his threat to go after the crew. Wozniak faces the impossible decision to pick between his team and Ayres (guest star Anna Gunn) just as his son, Nate, makes an effort to reunite.

Harlee (Jennifer Lopez) makes the chilling discovery that someone is texting Cristina (Sarah Jeffery) as her dead ex, Miguel. The case of a missing kid leads Wozniak (Ray Liotta) to uncover a local dealer who uses underage mules and reminds Loman (Dayo Okeniyi) of what their unit is all about. The crew gets caught in a brutal ambush.

Harlee (Jennifer Lopez) and Wozniak (Ray Liotta) lead a manhunt for the gunmen who ambushed the crew and unearth the key to taking down Bianchi (Ritchie Coster). The crew bands together against the threat of Verco (guest star Dov Davidoff) who has finally obtained evidence of their corruption. Stahl (Warren Kole), suspended from the FBI, goes rogue to complete his quest to link Harlee to Miguel's death.

Events take a tragic turn when Harlee and Wozniak lead the crew on a dangerous mission to steal Bianchi's secret ledger and take down the mobster once and for all.

Harlee (Jennifer Lopez) helps Nava (Gino Anthony Pesi) cover his tracks after a violent encounter, revealing a side of herself Nava's never seen before and putting their relationship in jeopardy. Wozniak (Ray Liotta) faces a ghost from his past in order to take down a new enemy in his present. Stahl (Warren Kole) gets a critical piece of information in his hunt for the truth about Miguel.

In a dramatic confrontation, Wozniak (Ray Liotta) faces the ally who betrayed him and makes his most difficult choice yet. Meanwhile, Stahl's (Warren Kole) fanatical plan to take Harlee (Jennifer Lopez) down for murder finally pays off, forcing Harlee to get dangerously close to the man who's obsessed with her In the end, Harlee and Wozniak's desperate efforts to save themselves and the crew lead to shocking consequences for both.