Road To Perdition by Max Allan Collins

A stoic Depression-era mob enforcer sees his world collapse after a betrayal that destroys his family; he flees with his surviving young son and sets out on a grim road of revenge while hunted by other killers. Their flight forces the father to teach the boy harsh lessons of survival, turning their journey into a tense meditation on loyalty, vengeance, and the moral cost of violence as the two struggle to protect each other against the criminal underworld.

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