Neale and Pedro fly cargo between Chungking and Calcutta. When their buddy Bill is murdered they investigate. Neale meets Bill's fiancée Virginia and becomes suspicious of a deeper plot while also falling for her charms.

Shortly after Pearl Harbor, a squadron of PT-boat crews in the Philippines must battle the Navy brass between skirmishes with the Japanese. The title says it all about the Navy's attitude towards the PT-boats and their crews.

The nefarious Dr. Fu Manchu searches for the keys to the tomb of Genghis Khan, in order to fulfill a prophecy that will enable him to conquer the world. His nemesi, Dr. Nayland Smith and his associates fight to keep the evil doctor from getting his hands on the keys. In 1943 the serial was edited together into a feature movie also called Drums of Fu Manchu.