When the Dutch resistance brings in Carla Van Oven (Lana Turner) to spy on the Nazis, Col. Pieter Deventer (Clark Gable) initially suspects she could be a double agent. Van Oven eventually convinces Deventer of her character, and when she is sent into occupied territory, she joins up with a rebel leader known as "The Scarf" (Victor Mature). As the resistance endures severe losses and their missions fail, Deventer starts to wonder whose side Van Oven is fighting on.