Captain Midnight was only one of the many aviation serials released during World War II, whose leading characters were derived from early pulp magazines and radio show favorites.

He is assigned to neutralize the sinister Ivan Shark, an evil enemy scientist who is aerial bombing major American cities with his unmarked aircraft.

Shark is after a new aviation range finder invented by the altruistic scientist, John Edwards, whose beautiful daughter, Joyce, they attempt to capture in order to blackmail the patriotic inventor.

Captain Midnight and the Secret Squadron continually battle the henchmen, thwarting Shark's evil plans, while avoiding destruction at every turn by making daring escapes during the serial's 15 weekly chapters.

Source:[1] The serial was released in Latin America in November 1942, under the title El Capitán Medianoche, and was shown in English with Spanish subtitles.