Captain Jim Leslie, a US Air Force pilot, is transferred to a remote Alaskan base not far from the Soviet border. Here he meets his old friend Harris again and falls in love with Brenda, the commander's daughter. He then comes into conflict with her fiancé, Senator Gordon Gray. At his instigation, he is sent on a dangerous mission with Harris and the navigator Hester: During a storm, the buoys deployed to locate Soviet submarines must be checked. During the emergency landing on an ice floe, Harris suffers a life-threatening injury. They are in Soviet territory, but in view of the situation Jim disregards the radio ban and sends a distress signal. A Soviet submarine appears, Harris is operated on and they are helped to get the plane ready for take-off. Arriving at the base, Jim is arrested. Brenda turns her back on him.