Philip Ahlm as German Chief Petty Officer; Al Bennett as Naval reservist; Bill Brande as Naval reservist; William Collier Sr. as Mugs O'Flaherty; Leonard Davison as Naval reservist; Joseph Depew as Naval reservist; Francis Ford as Eric; Robert Ford as Naval reservist; Hans Fuerberg as Fritz Kampf; Warren Hymer as Kaufman; Walter C. Kelly as Chief Mike Costello; Larry Kent as Lt. McGregor; Marion Lessing as Anna Marie Von Steuben; John Loder as Franz Shiller; Mona Maris as Fraulein Lolita
Rating
Cinematography
Language
English
Plot
In the waning days of WWI, a U.S. 'Mystery Ship,' sets sail for the coast of Spain towing a submarine. Their mission is to find and sink a U-boat that has been especially effective in attacking Allied shipping. Posing as a harmless schooner, the mystery ship is in fact fitted with a formidable gun capable of sinking a U-boat. Stopping in the Canary Islands to refuel, the crew interacts with locals involved with Germans, and with Germans themselves, including the sister of the U-Boat commander, who is lurking offshore waiting for the coming battle.