Mobster Ma Webster rules her clan with an iron hand, taking charge of all their robberies despite the protests of George Frost, the only member of her gang who is not her son. On Christmas Eve, Ma, George and her sons Eddie, Charlie and Tom, rob the Centre City bank, but are warned to get out of town by her other son Bert, who disdains their criminal activity and is studying to be a lawyer. Ma and the gang go on a crime spree across the states, receiving $300,000 in ransom for kidnapping, and additional cash from various robberies. Aware that the serial numbers on the ransom money have been recorded by federal agents, they arrange with fellow crook Pan to trade the money $100,000 in unmarked bills, but take the bills and kill him instead, They are unaware, however, that the police have found a list of the serial numbers for all Pan's bills in his coat pocket. Federal agents Scott Langham and Ross Waring are put on the case, and trace the Websters to a Southern town, where Ma is posing as a socialite. The Websters elude the police, but are forced to live meagerly while hiding out in cheap hotels. By the next Christmas, Ma returns to Centre City to visit Bert's baby boy. While she is out, her boys hold up a store, but Charlie is killed and Tom is arrested. Bert represents Tom at his extradition trial, and convinces him to plead guilty and return willingly to the city of the kidnapping. When George wants to go his own way, Ma and Eddie kill him, then hire Stitch Torey to get Tom away from the police. Their attempt fails, however, and most of Torey's gang perish. After a year, Ma and Eddie have developed a low profile while Eddie works at a cannery to support them, and Ma becomes neighborly. Unknown to Ma, Eddie arranges a hideout for some robbers he hopes to join up with and gives them a case of canned food, but the criminals' car crashes and the police get Eddie's fingerprints from the cans. On Christmas Eve, federal agents attempt to arrest Ma and Eddie, who respond with gunfire. In the hail of bullets, Eddie is killed and Ma is finally arrested.