Nick Romano lives in a poor tenement building on the south side of Chicago with his well-meaning but drug-addicted mother, Nellie. She encourages him to pursue his piano-playing talent in hopes that it will bring him a better life. Nellie's neighbors, like the alcoholic ex-lawyer who secretly loves her, help her in keeping Nick away from Louie, the resident drug dealer. But a chance meeting between Nick and Louie could change things forever.

After a demonstration of new PT boats, navy brass are still unconvinced of their viability in combat, leaving Lt. "Rusty" Ryan frustrated. After the attack on Pearl Harbor, however, Ryan and his buddy Lt. Brickley are told they can finally take their squadron into battle. The PT boats quickly prove their worth, successfully shooting down Japanese planes, relaying messages between islands, and picking off a multitude of enemy ships.

When police officer Moe Finkelstein and his colleague Officer Salomon are ordered to serve as bodyguards to German consul Karl Baumer by the mayor of New York City, Finkelstein turns in his badge, convinced he has to quit the service because the man is a Nazi.