Shane is burdened with guilt after learning that Detective Kavanaugh planted a lie that led him to kill Lem. While Kavanaugh does everything he can think of to discredit the Strike Team, including planting evidence and coercing a trusted informant, Vic remains unaware of the killer's identity and sets out to prove that it was mobster Guardo Lima. Once Kavanaugh's plan unravels and Vic lures Lima back from Mexico to get revenge, he discovers - too late - that he's made a fatal mistake. And though Shane finally admits he murdered Lem to stop him from testifying against them, Vic refuses to forgive. A deadly drug war between rival Latino gangs turns political with the involvement of a prominent real estate baron with dirt on Aceveda and a corrupt Mexican government official, and Shane turns to the Armenians for protection, only to have his misplaced faith put the Mackey family in danger.