M-G-M filmed the mystery of the year in Holland!

When the Dutch resistance brings in Carla Van Oven to spy on the Nazis, Col. Pieter Deventer 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". As the resistance endures severe losses and their missions fail, Deventer starts to wonder whose side Van Oven is fighting on.