Three Secrets that Changed the War.
A mighty drama of the sea. (One-sheet poster).
MAN THE LAFFBOATS!
The undercover...underwater war that shattered the sea...and shook the earth !
DEATH Catapulted from the Depths!
SAVAGE PASSIONS aflame in the North Atlantic! Unleashed by treachery...hate...violence!
The Captain Knows Members of His Submarine Crew are Enemy Agents - But Who?