Near the end of World War II, German scientists, goaded on by Hitler and his dreaded SS chief Himmler, have developed and tested a secret death ray. When the Allied command cracks the Nazi code, General Eisenhower hurriedly assigns Ken Prossr and his team to find that terrible weapon and destroy it. Time is of the essence, since Hitler plans to unleash it against the advancing Allied armies in just a few days. Col. Prossr and his men parachute into the Austrian Alps and a British agent guides them to the hidden valley where Hitler's "miracle weapon" is being assembled. She has learned that the death ray will come from one hundred jet planes concealed in caves. Prossr and his team fight their way into a dam, force open its gates and flood the caves. Barely in time, the Nazi planes and their death-ray equipment are totally destroyed. So, also, is the factory producing them in the hidden valley.