Mary is a nurse at a Lancashire POW camp. Life at work is difficult but fulfilling. Soon, she meets Frank, a guard who has been watching her for weeks. But Frank is difficult to love and it's not long before Mary decides to break it off. Matters come to a head when Frank puts two and two together and realises that Mary is about to embark on an affair with one of the camp's German doctors. Frank is not the kind of man who will take no for an answer...