Lily Dallas is a highly intelligent ex-con who has a history of committing bank robberies. This time she and her husband George 'Blackie' Dallas, who is known for his deft use of a Tommy gun, kidnap a well known and very rich businessman Thomas B. Randall and demand $300,000 ransom. Mrs. Randall follows their instructions and doesn't contact the police until after she has paid the ransom so Ness puts out a rumor that all of the bills have been marked.