Rock Island, Illinois -- 1929. Michael O'Sullivan is a good father and a family man -- and also the chief enforcer for John Looney, the town's Irish Godfather of crime. As Looney's "Angel of Death," O'Sullivan has done the bidding of Chicago gangsters Al Capone and Frank Nitti as well -- but when a gangland execution spells tragedy for the O'Sullivan family, a grieving father and his adolescent son find themselves on a winding road fo treachery, revenge, and revelation.