In a steamy new drama, Jennifer Lopez stars as sexy New York detective and single mother Harlee Santos, who fell in with a tight-knit group of dirty cops, taking bribes and protection money that she uses to provide the best life for her honest, talented daughter. But when she's trapped by the FBI and forced to inform on her own "brothers", she'll have to walk the fine line between love, loyalty, honor and betrayal, and try to keep it together for her daughter's future.
In a dramatic confrontation, Wozniak faces the ally who betrayed him and makes his most difficult choice yet. Meanwhile, Stahl's fanatical plan to take Harlee 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. *SEASON FINALE*
Unable to provide Donnie and Linklater to the FBI, Harlee makes a deal with Stahl to exchange her own immunity for that of her crew. Harlee comes face to face with Miguel who reveals his darkest side as he demands to be a part of Cristina's life.
Harlee makes the chilling discovery that someone is texting Cristina as her dead ex, "Miguel." The case of a missing kid leads Wozniak to uncover a local dealer who uses underage mules and reminds Loman of what their unit is all about. The crew gets caught in a brutal ambush.
Harlee helps Nava cover his tracks after a violent encounter, revealing a side of herself Nava's never seen before and putting their relationship in jeopardy. Wozniak faces a ghost from his past in order to take down a new enemy in his present. Stahl gets a critical piece of information in his hunt for the truth about Miguel.
Wozniak goes after Bianchi for breaking their agreement. Harlee seizes the opportunity to unite the team around an illegal mission to repay Tufo's brother's debt to a local drug dealer. Stahl 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 just as his son, Nate, makes an effort to reunite.
Harlee and Wozniak must face the consequences of the disappearance of the heist's money. Out of options, Harlee approaches the FBI and promises to find the money and deliver Wozniak and his partners if Stahl keeps her in play.
Harlee and Wozniak lead a manhunt for the gunmen who ambushed the crew and unearth the key to taking down Bianchi. The crew bands together against the threat of Verco who has finally obtained evidence of their corruption. Stahl, suspended from the FBI, goes rogue to complete his quest to link Harlee to Miguel's death.
Harlee and Wozniak lead the crew on a dangerous mission to heist Bianchi's secret ledger and take down the mobster once and for all. But the plan takes a tragic turn when the events our heroes set in motion put one of their own in harms way, forcing Harlee to turn to an unlikely source for help.
On the day of the heist, Harlee realizes she misplaced her trust in Stahl but it's too late to back down. Harlee tries to get immunity for her crew as she participates in the heist knowing that it will lead to Wozniak's arrest. Miguel discovers Harlee's secret. Loman unwittingly witnesses the heist just as the exchange goes terribly wrong.
Wozniak's suspicions land on Saperstein, forcing Harlee to convince Stahl to arrest Saperstein in order to keep him safe. Harlee visits her abusive ex, Miguel, who tasks her with tracking down the man who committed the murder for which he is imprisoned.
Harlee and Wozniak investigate Caroline's (Nava's ex-fiancée) murder, putting Harlee and Nava's 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 as Loman uncovers a much deeper secret.
Following Harlee's brave confession to the entire crew that she has been informing for the FBI, the team grapples with Harlee and Wozniak's betrayal. With their team falling apart, Harlee and Wozniak come up with a desperate plan to neutralize Bianchi. However, their actions have unforeseen consequences because the Mafia fires back.
Following Wozniak's discovery that Stahl's target is his close friend and Mayoral Candidate, Julia Ayers, Wozniak launches an all-out war with Stahl. Meanwhile, Harlee 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.
Harlee focuses her sights on taking down the intelligence unit. Stahl’s continued obsession brings him closer to New York. Wozniak uses Wallace as Espada struggles with keeping secrets from Tufo.
After Wozniak refuses to play ball with the FBI, Stahl turns up the heat on Harlee 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 applies pressure to each member of the crew to discover what really happened to Donnie Pomp.
The mafia seeks revenge on Harlee by framing her for murder. As Harlee works against the clock - and her own crew - to cover her tracks, Wozniak fights to keep his cop-family together when evidence of an old crime puts pressure on the already splintering team. Stahl cozies up to Cristina, getting one step closer to the truth about Miguel.