The rift between Kyle and Frank grows when Kyle refuses to adhere to one of Frank's morally ambiguous rules, but the pair must put aside their differences when they learn the notorious hitman known as "El Cucuy" is targeting members of the Russian mob in Los Angeles.

Deputy Chief Lockhart opens an internal investigation into a past shooting which could cost Frank his badge and freedom, forcing Kyle to help Frank clear his name or risk losing the one man who could help him solve his father's murder.