After a bust on an Armenian gang's drug delivery, Julien sees the Strike Team take a portion of the drugs for themselves. Subsequently, the vehicle holding the drugs is stolen on Shane's watch, forcing Vic to track them down before Aceveda is able to pin the theft on him.

As Dutch uncovers a lead to the serial killer, a reporter's questions force Aceveda to explain problems he thought were buried fair in the past, while Vic assists Connie as she tries to quit crack cold-turkey in a desperate attempt to keep her son, leaving the other Strike Team members to investigate a strip-club mugging ring on their own.

Aceveda turns to Claudette after a double homicide raises ire and fear within an ignored community. Vic is forced to help Gilroy avoid being implicated in a hit-and-run, while Shane and Lem follow the trail of a gunrunner with a penchant for cockfights.

As Vic gets closer to finding his family, the Strike Team focus their attention to Armadillo after he burns down Tio's business, an act that threatens to expose Vic's protection racket. As Claudette gets closer to the truth about Vic's connection to Tio, Dutch is accompanied by the civilian auditor to solve the murder of a meter maid, while Danny and Julien intervene between two feuding neighbors.

When Vic discovers that Ronnie has been burned as payback, the rest of the team set their sights on taking Armadillo off the streets for good. Meanwhile, Claudette makes headway on her investigation into Vic after a conversation with Corrine, and Dutch takes Danny under his wing as they attempt to track down the suspect of a Thai Town beating.

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 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.

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.

When a mole in the treasury department is discovered and the framed suspect in the Armenian money train robbery turns up missing, the Strike team race to find the suspect before their cover is blown. Meanwhile, Claudette attempts to make amends with the Decoy Squad by going undercover to help them on a case.

Mackey tries to help an old acquaintance find a wayward teenager, but the search quickly turns ugly when the missing teen appears to have been involved in a shoot-out. Meanwhile, Shane heads out into the field with his new partner Army, teaching him shady police tactics and seeing how far he'll go to be partnered up. Plus, Aceveda spends his last day trying to bury Vic for good, which makes things difficult for Rawling trying to take his place.

Vic and his crew track down the Russian who was involved with the cop murders, but they lose control during his interrogation and the hit man dies in an explosion before they can get any answers. Meanwhile, Aceveda is blackmailed by the man who assaulted him. Plus, Rawling's seizure is on the verge of being shelved.

As racial tension in the area escalates, the Strike Team attempts to end a race war, while Claudette and Dutch investigate a riot at a high school. Meanwhile, an Internal Affairs officer begins his investigation of Vic and the Strike Team by first zeroing in on Lem. A pregnant Danny refuses to reveal the identity of the father, and Julien begins training a rookie cop named Tina Hanlon.

Via a bug planted in the clubhouse, Kavanaugh monitors the Strike Team as they investigate an illegal prescription drug ring that is proving to be deadly for the people of Farmington. While working on a missing person’s case, Dutch attempts find out what Claudette is hiding.

To the dismay of his friends, a weary Lem is thinking about accepting a deal from the D.A. where he has to plead guilty to the heroin charges. With no other choice, Vic reluctantly meets with Antwon in order to ensure Lem’s safety in prison. Meanwhile, unforeseen circumstances that are beyond Claudette and Dutch’s control might cause irrevocable damage to their friendship.

With the Barn grieving over the loss of one of their own, Vic's out to avenge his friend's murder, but finds himself in the crosshairs of Kavanaugh. Claudette assigns the Strike Team to investigate the torching of a methadone clinic. Meanwhile, Julien and Tina look into a robbery/assault at a porno shop, and Dutch makes a horrifying discovery in San Marcos.

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.

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