When Ensign Peter Maxwell was called up from the reserves just after Pearl Harbor, he didn't think he'd be defending his country by leading the Navy choir. After two years entertaining VIPs he wants to see some action, and a posting on the new ammunitions ship, the USS Liberty Hill Victory, seems just the ticket. Unfortunately, the ship's captain has no respect for junior officers like Maxwell, and even less for the African-Americans who make up his crew. Despite tensions between captain and sailors, the two-week shakedown cruise goes unexpectedly well. But as the ship approaches San Francisco's Port Chicago, a series of horrific explosions virtually destroys the port. Then the Liberty's second in command is murdered. There is an enemy within, and Maxwell will do everything to stop him, including putting himself on the front line of danger.