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.

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 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.

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 and Wozniak attempt to deal with the consequences of the heist's money disappearance. Harlee informs the FBI that she will get the money back.

Harlee and Wozniak, still dealing with the fallout from their near death experiences, discover a grisly crime scene riddled with mystery.

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.

Wozniak enlists the crew to make a dangerous move against the Intelligence unit as Harlee struggles to stay on her new path.

Harlee discovers that the intelligence unit’s involvement in criminal enterprises goes deeper than she thought. Ramsey strikes back. Tufo pulls away from the crew. Loman meets a girl.

Harlee uncovers a betrayal. Cole tries to avoid Ramsey’s reach. Wozniak attempts to negotiate with the intelligence unit.

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 Santos, a detective from a tight-knit group of Brooklyn cops with questionable tactics, is arrested by an FBI agent who wants to make her an informant. Co-stars Ray Liotta.

Harlee struggles with becoming an FBI informant while Wozniak suspects every member of his crew. Paranoid that Wozniak's search will lead to her, Harlee suggests polygraphng the entire crew, a plan that backfires. An appeals case sends Wozniak to watch tapes from his first encounter with Harlee, revealing a dark secret from their past. Meanwhile, Espada helps Tess deal with her husband's infidelity.

Loman's guilt over the death of an unarmed suspect becomes a liability for the crew, forcing them to test his loyalty. Wozniak sends Harlee on an errand that reveals he has a silent partner in the big score. Wozniak realizes Donny has been withholding information. Harlee feigns cooperation with Stahl, but unwittingly leads the FBI to incrimmating evidence,

Harlee and Tess intercept a heroin shipment from a local drug lord who discovers Wozniak's secret and tries to use it as leverage to get his confiscated drugs back. Harlee fears Stahl's interest in her goes beyond the professional, believing he is invading her privacy, and resorts to spying on him with the help of an old friend. Tess tries to use Espada to get back at her husband.

Harlee refuses to give Stahl incriminating evidence against Wozniak but hands over a fully resolved unoffical investigation that Tess and Espara initiated when they moved a body by Tess' house found to be murdered with a 3D printed gun. Wozniak confronts Harlee who executes a dangerous bluff.

Harlee's collaboration with Stahl (Warren Kole) uncovers Wozniak's secret relationship with Donnie.  Wozniak decides to take charge of the big job after picking up a package that turns out to be a kidnapped man.  A mysterious call to Saperstein's desk forces the crew to face their mixed feelings about their fallen friend and ultimately decide to preserve his memory.

Harlee Santos takes drastic measures to cover up the murder of her abusive ex, Miguel. Lieutenant Matt Wozniak makes a deal with FBI Agent Robert Stahl to keep himself and his crew out of jail but soon discovers Stahl has led him into an impossible trap. As the crew deals with the fall-out from the failed heist, Tess struggles to keep her painful gunshot wound under wraps.

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 as 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.

Harlee and Wozniak secure more details on the big score and meet Donnie's silent partner, who reveals himself to be an DEA agent.  They learn the big score is an armored car heist.  Wozniak takes interest in a fellow marine veteran who is suspected of murder under dubious circumstances.

Wozniak finds it hard to deal with guilt as he attempts to deal with an unfinished task. Harlee needs to protect Saperstein whilst holding the unit together.

Realizing that Stahl will stop at nothing to arrest Julia Ayre, Harlee decides to investigate on her own and determine whether there's any truth in his allegations of Ayers active business with the mob. Wozniak 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.