Mobster "Baby Face" Martin returns home to visit the New York neighborhood where he grew up, dropping in on his mother, who rejects him because of his gangster lifestyle, and his old girlfriend, Francey, now a syphilitic prostitute. Martin also crosses paths with Dave, a childhood friend struggling to make it as an architect, and the Dead End Kids, a gang of young boys roaming the streets of the city's East Side slums.

In Tiger Bay, the docklands of Cardiff, rough-and-tumble street urchin Gillie witnesses the brutal killing of a young woman at the hands of visiting Polish sailor Korchinsky. Instead of reporting the crime to the authorities, Gillie merely pockets a prize for herself — Korchinsky's shiny black revolver — and flees the scene. When Detective Graham discovers that Gillie has the murder weapon, the fiery young girl weaves a web of lies to throw him off course.

A savings-and-loan bank is robbed; later, a police wiretap identifies meek bank teller Leon Poole as the inside man. In capturing him, detective Sam Wagner accidentally kills Poole's young wife, and at his trial Poole swears vengeance against Wagner. Poole begins his plans to get revenge when he escapes his captors.

Hoppy, California and Johnny partner up with brother and sister ranch owners, two of several who are having their access to water blocked by a dam owned by a greedy merchant in town, who is intent on driving them out and taking their land for himself.

A young deaf women confronts desperate crooks who are using one of her remote resort cabins for a hideout.

A successful prostitute is generous to a poor old friend. He becomes jealous, follow her and kills her, hide the body and fake his own suicide.