The Strike Team's attempt to play by the book comes to an abrupt end when they discover that the Byz Latz and the One-Niners are attempting to alter the balance of power by acquiring MP5s. Meanwhile, Claudette and Dutch investigate the murders and foot severance of Armenian men by the Armenian mob, a case that draws them closer to the truth behind the money train robbery.

Vic decides to use some of the money train robbery cash during a gun-running sting operation, but after it goes awry, tension within the Strike Team begins to mount as its members attempt to rectify Vic's mistake. Meanwhile, Dutch and Claudette seek the help of a college student named Esteban who was the only survivor in the murder of two Latino gang members.

A prostitute and friend to the late Connie named Farrah seeks the help of Vic in an effort to bring down her pimp. After failing to convince Vic to help her, Farrah goes to Claudette, who assigns Vic to the case against his wishes. Meanwhile, Dutch investigates the rape of an elderly woman.

The newly arrived Decoy Squad and the Strike Team go head to head in the investigation to solve a car-jacking case. Dutch gets in over his head on an attempted murder case.

Vic struggles with Claudette's new supervision of the Strike Team. Marked bills lead Aceveda and a federal agent closer to the truth about the Armenian money-train heist in an episode with a recurring motif of people not reporting crimes against them.

Vic and the Strike Team decide to take risky measures to protect themselves from being linked to the Money Train heist. Unfortunately, their plan is interrupted when one of Vic's open cases is suddenly linked to a Narco Corrido song.

An oversight puts Waylon and Trish in serious danger during an undercover job and Claudette is to blame. Meanwhile, Tommy makes a drastic decision when he realizes nobody in the Barn can help him get back on the job.

When two high profile murders are linked to each other, Aceveda orders Wyms to get the entire Barn involved before gang and racial violence breaks out. Mackey uses the case to leverage himself and the Strike Team back into the streets of Farmington.

Aceveda finds himself in a near fatal confrontation, and enlists Vic to help him take down the suspects in order to help service his own personal agenda. Meanwhile after losing her position of power, Claudette rejoins Dutch on the search for the cuddler rapist as they get a stunning break in the case.

During a routine bust on bangers, Vic and the Team discover a money laundering ring that reaches far and wide in the crime community. Meanwhile, Dutch takes the chilling confession of the man who was arrested in the serial-rape case, and Danny goes undercover.

With an Armenian hit-man hot on their trail, the Strike team sweeps the streets of the Armenian community to find him before he finds them. After catching a break, Aceveda's suspicions grow about the Strike Team's involvement with the Money Train robbery. Meanwhile, Dutch and Claudette investigate a case that could repeal hundreds of convictions, which leaves Claudette having to choose between her conscience and her career.

With Farmington on the brink of a gang war, Monica and Vic race to find the catalyst and stop the bloodshed, enlisting Antwon's help along the way. Still in the doghouse, Dutch decides to take action in thawing the relationship between Claudette and the D.A. Danny and Julien get up close and personal with the Farmington 1-Niners, while Monica looks to Vic for support when the implementation of her property seizure policy challenges her morality.

The Strike Team tries to develop a strategy to deflect the Internal Affairs investigation as Vic finally comes face to face with Kavanaugh. Meanwhile, Tina goes undercover to help take down a sex-trafficking ring; and friction between Claudette and Dutch deepens when she reopens one of their past cases.

After being badly beaten, Shane's life spirals even more out of control as his guilt continues to eat away at him and his marriage begins to fall apart. Vic and Ronnie try to learn who was responsible for Shane's attack. Meanwhile, under the new leadership of Kevin Hiatt, Claudette assigns the Strike Team to investigate the San Marcos murders. Dutch and Billings make progress in a serial rapist case.

After Vic disowns him, Shane turns to the Armenian mob for help. Vic gets more involved with the San Marcos investigation, while Dutch and Billings are able to track down someone who survived the massacre.

Vic challenges Shane and deals with threats to his family; a federal agent arrives in Farmington to investigate a recent wave of violence.

Vic works an angle to make himself valuable to the Armenian mob; Corrine finds herself in a surprising legal jam; Tina targets a producer of adult entertainment.

Vic sets into motion plans to end the gang threat as his relationship with Cassidy deteriorates; Dutch and Billings investigate a possible sleepwalking murderer.

A prostitute from Vic's past is the key to taking down a violent drug dealer; Dutch worries about Claudette's health; Danny takes drastic measures to protect her child.

A local priest may be protecting drug dealers; Dutch and Billings close in on attempted cop killers; Corrine learns uncomfortable truths about Vic.

Vic closes in on Shane, Mara and their sick young son; Claudette dismantles the Strike Team; Pezuela offers Acevada "assistance" for his mayoral campaign; Rita Denton (Frances Fisher) comes on to Dutch; and Billings' ex-wife and daughter are fearful when a registered sex offender moves into their neighborhood.

While Shane remains holed up in L.A. with Mara and Jackson, Corinne decides to cooperate with Dutch and Claudette, who's now spearheading the LAPD effort to bring down Vic. Meanwhile, Vic plays Aceveda, Pezuela, Beltran and ICE against each other. But Ronnie's tempted to simply give up and run to Mexico. "And you should run too man" he tells Vic.

Corrine agrees to be Vic and Shane's go-between and also agrees to cooperate with Claudette and Dutch as she does so. Meanwhile, Vic comes to an understanding with Aceveda and seeks one out with Olivia; and Claudette assigns Ronnie to work with Julian to investigate the murder of a high-school football star, keeping Ronnie out of the barn and unable to intercept the letter Shane sent to Claudette detailing the Strike Team's "sins."

Olivia joins forces with the Strike Team to catch a Mexican drug king and his shipment. Meanwhile, Dutch cleans up Billings' mess, and the death of a woman associated with the Strike Team prompts an investigation by Claudette.

Officers in the Barn investigate a woman's disappearance and the arrival of a large drug shipment; lives change forever.