After Big Butch Dooley, a Flying Tiger, lands his P-40 plane in the ruins of a Chinese village, he rescues a wounded boy, who has been orphaned by the war, and takes him back to his unit. The child is adopted by the Flying Tiger group and taught commando tactics. Eventually, however, Big Butch and the other Tigers realize that the boy, now called Little Butch Dooley, needs a proper education and send him to the Temple Missionary School, which is operated by the kindly Doc Temple, under the still neutral American flag. While there, Little Butch organizes the other refugee children and trains them in guerrilla warfare. In spite of Doc's pleas, the orphans steal away from the mission at night in order to prey on the Japanese. During one of their forays, the children, dubbed "The Little Devils," secure a large store of Japanese gasoline for the Flying Tigers. Although Little Butch is wounded during the raid, he continues to lead his group, until two of them are taken prisoner while blowing up a Japanese supply base. When Doc pleads with a Japanese officer for their release, he learns about the attack on Pearl Harbor and is told that, as he is now the enemy, he, too, will be taken prisoner. Through a scheme devised by Little Butch, Doc is rescued, and soon after, the Japanese bomb the mission. Later, an American plane crashes, and the Little Devils race with the Japanese to reach the wreck. The Little Devils find the American plane first and are surprised to discover that the pilot is Big Butch. After treating Big Butch's wounds, the Little Devils help him cross a river and return safely to the Chinese lines. As the boys are escaping, however, a Japanese patrol converges on them, and they sacrifice their lives while shooting it out with the enemy. Sometime later, the spirit of Little Butch rides on a bomber with Big Butch, as he drops a cargo of explosives on Tokyo.
