Shadow of Terror plot
"TRAPPED... By Killers On Trail Of The Atomic Bomb!"
Howard Norton is a scientist who has a formula for making an atomic bomb. Howard is chased by mobsters one day. These mobsters, led by Victor Maxwell, manage to capture Howard during a train journey. They knock him unconscious, steal his formula documents and then throw him off the train. Later Howard wakes up and somehow manages to reach a ranch. Joan Rutledge, the ranch owner, tends to his wounds and helps him as he recovers from amnesia. Both are still bothered by the gangsters. In an unguarded moment, Howard and Joan manage to flee and head for the desert. However, the gangsters give chase.