Tony Sanchez, an undercover narcotics cop and close friend of Joe Dominguez is killed by mobster Maximo Ortiz. Joe promises Tony's wife Denise that he will get the people responsible even though Tony's killing was ordered by Ortiz already in prison, sentenced for 8 years. After a frustrating interrogation of an Ortiz thug who reveals nothing, Joe decides to go undercover to get Ortiz.
Inside San Julian Prison, Joe pretends to be Francisco Chuy Juarez ("Chewie") to find out about Ortiz's expected large "Shipment of Century." After befriending Ortiz by beating Ortiz at handball and beating up a white supremacist named Billy Ray Tucker, Joe asks Ortiz to kill his unfaithful wife outside the prison walls. The hitman turns out to be the Head Guard of the prison, Jack Archer.
Meanwhile Nash is busy in court testifying in the McCallister case, with Nash's sister Stacy prosecuting the case. Stacy also wants to write out a will for their dad Nick, which causes consternation between Nash and Stacy. Nick has a patch of land which has turned out to be valuable real estate worth $300,000. After Harvey's wife Bonnie has left him, Harvey has moved in with Evan.
Harvey visits Joe in prison as his lawyer, as does Bryn Carson as his floozy wife.
Harvey and Bryn pass information and smuggle out tapes Joe has recorded from Ortiz's cell. On the outside, the SIU busts Ortiz's gambling operation and discover that Ortiz has sold his operations and is moving out.
Joe has befriended an old timer convict named Larry to help Joe out. A Colombian drug lord named Santiago Cordero is also at San Julian Prison to testify against the Cali Cartel. Joe discovers that Cordero is paying Ortiz ten million dollars for both crime bosses to escape out of prison with the aid of Head Guard Jack Archer.
After discovering that Archer is the killer of Tony Sanchez, Nash orders Harvey to arrest Archer at the prison. Harvey gets taken prisoner along with Joe when both are locked inside an isolation cell. With the help of the convict Larry, Harvey and Joe escape from their guards, and foil Ortiz and Cordero's escape. Harvey shoots Archer, and Joe arrests Ortiz for murder.
Joe meets Denise to tell her that her husband's killer has been taken down. Nick decides to use his $300,000 to buy a race horse to earn more money, but to the worry of Nash and Stacy.
For more, see commentary for Episode 22