Don Winslow of the Navy (1942)

"The Navy's ace Intelligence Officer...blasting spies and saboteurs to save a nation's vital lifeline!"

A movie serial in 12 Chapters: US naval officer Don Winslow is given command of Tangita Island, near Pearl Harbor, where a ring of saboteurs is trying to destroy ships carrying supplies to the troops stationed in the islands and sabotage the war effort under orders from an unknown leader.