Gangsters emerge for the funeral of a high-level drug dealer, leading to chaos on the streets. Meanwhile, Lydia and Ruben unearth police corruption while probing a murder; Ben has suspicions about Sammy; John spirals deeper into loneliness.
John desperately tries to save Hicks while facing dark truths from his past. Meanwhile, Sammy is haunted by a lie he told; Lydia and Ruben search for a John Doe; and Ben takes his relationship with Elena to the next level.
The cops confront their greatest fears. Elsewhere, Lydia is shattered by the death of a baby; Sammy's altercation with Tammi is scrutinized; Cooper seeks comfort in Hicks; and Ben inches closer to Brooke all while continuing a relationship with Elena.
John mulls over the life he'll have once he leaves the LAPD; Lydia bonds with a man she sent to death row in the past; an annoyed Sammy becomes a tabloid celebrity in the wake of a heroic act; Ben makes a questionable decision while tracking a drug dealer.
Season 5 opens with John at odds with his new trainee, a veteran from Afghanistan. Meanwhile, Lydia tries to juggle motherhood and detective work; Ben associates with a shady band of cops; and Sammy gets caught up in a nightmarish custody battle.