Outraged by the attack on Pearl Harbor, Muggs, Danny, and the rest of their gang want to enlist. Turned away because of their age, they take out their frustration by harassing an Asian shopkeeper. When the shopkeeper is found dead soon afterward, the boys learn that he was Chinese, not Japanese. Determined to atone for their behavior, the gang stumbles across evidence that a real group of Japanese spies is operating in the area, and they become determined to expose them. Meanwhile, Danny is troubled further by the news that his older brother has been dishonorably discharged from the Navy.