While Vic continues his search for Corrine and their children, the Strike Team allow more drugs into Farmington through a corrupt connection. But when their latest shipment turns bad, they head to Tijuana to uncover the culprit behind the poisoned cocaine. Meanwhile, Dutch and Claudette try to track down the man responsible for "fire-necklacing" the leaders of two separate gangs.

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.

Still fuming from the murder of Tio and his brawl with Armadillo, Vic takes a day off to reconnect with his old partner, and soon sets out to help him get revenge against the thug whose complaint forced him into retirement. Meanwhile, an amputated arm sends Dutch and Claudette in search of the sadomasochistic criminal behind the torture and mutilation of a woman who may still be alive, and tensions brew between Danny and Julien after Julien fails to back up Danny's side of the shooting to IAD.

Now that Vic is back to work, he and Shane go undercover as dirty cops to find the man behind a robbery and murder. Dutch and Claudette track down an old rival of Claudette's after a turned-in gun is found connected to an unsolved case, while Aceveda assigns Julien and Danny to watch over a Korean parish in an attempt to secure the Asian vote in the election.

Grade school heroin dealing prompts Vic to increase his efforts to bring down Armadillo, while Dutch and Claudette help a woman track down her Alzheimer's-addled mother.

The Barn mobilizes to investigate a massacre at a women's shelter, while Aceveda spends a day on the streets with Julien as the pair attempt to recover a child's stolen bicycle.

Vic and the Strike Team begin to prepare for the money train takedown, even though Armadillo's greenlight still has them on their toes. After embarrassing the department with the Bob and Marcy case, Dutch is forced to take any action necessary to prove himself in a new homicide, while Vic sets out to stop the abuse of a neighbor by her violent boyfriend, and Danny finally makes a stand against Yassirah.

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.

Flashback to the first day of the Barn. Under pressure to get results, Vic and the newly-formed Strike Team make an impression on the streets. Dutch and Claudette realize they make a good team, and Aceveda discovers he doesn't have as much power as he thought he would.

When Lanie's report on the Barn is leaked to the press early, everyone fears the prospect of losing their jobs, including Aceveda, who's mentioned as the reason for most of the precinct's problems. Meanwhile, Gilroy skips bail and winds up on Vic's doorstep looking for help, forcing Vic and Shane to deal with him while Lem shows Strike Team newcomer Tavon the ropes; and Claudette faces some of her own demons as she and Dutch try to uncover the culprit behind a possible robbery/homicide, while Danny comes to a startling realization.

With Ronnie's face healed, he comes up with an improved plan to take down the Money Train, and the Strike Team is all in. Unfortunately, a federal criminal comes back to Farmington, and the Team has to use every connection and resource to bring him in before Lanie submits her final report. Meanwhile, Dutch and Claudette investigate the rape of a young girl, and an old friend from the past reappears to make Julien's life hell.

While the Strike Team puts the finishing touches on the money train takedown, Vic works with Dutch and Claudette to find a missing child, while David gets an unwanted visit from the Chief and Julien is harassed by some of the other officers after Tomas outs him in front of them.

When a gang execution hits close to home for Claudette, Vic, Tavon, and Dutch work together to find the culprit before anyone else gets hurt. Shane, Lem, and Ronnie are forced to choose between hitting the money train without Vic or letting it go. As Aceveda prepares for the city council election, Danny receives some life-changing news, and the harassment inflicted upon Julien reaches a whole new level.