The Old Way (S04E01)

Just as they wrap up the Russian Mafia investigation, Caplan, Walter, and Roxanne are thrust into a new challenge with "Baba" Aroudj, the leader of the Turkish Mafia. Meanwhile, Vogel is in deep trouble behind bars. Determined to ensure Vogel can no longer cause any harm, Caplan realizes that achieving this goal requires him to confront a haunting chapter from his own past.