It's been 22 years since Vito has heard from Joe, but after Leo Galante's passing they both reunite and tie up loose ends and kill the last of they're enemies. But a few years later in 1975, a man named Louis Costello is a convict that finds out his brother has been killed by the Scarpa & Romeo Family. He eventually sides with Vito and Joe (leaders of the Scaletta Crime Family in Empire Bay & Los Ondas) to take down they're foe and find out on why his brother was killed.
