Kate "Ma" Barker, who was sexually abused as a young girl, grows into a violently powerful woman by the 1930s. She lovingly dominates her adult sons, grooming them into a gang of tough crooks. The boys include the cruel Herman, who still sleeps in Ma's bed; Fred, an ex-con who fell in love with another prisoner; and Lloyd, who gets high on whatever is available. They form a lethal, bizarre family of Depression-era bandits when they band together.