By the 1930s, Kate "Ma" Barker, who was sexually molested as a child, has developed into a fiercely strong woman. She lovingly governs and develops her adult boys into a gang of tough crooks. Among the boys are the harsh Herman, who still shares a bed with Ma; Fred, an ex-con who fell in love with another prisoner; and Lloyd, who gets hooked on whatever is available. They form a lethal and weird family of Depression-era robbers when they band together.