After the severe depression of the 1920s, Jan, a young Pole, is forced to seek work just across the border. His father and sister are brutally killed during the German invasion of Poland, and his brother remains on their small farm to assist the partisans.

As Nazi persecution increases, Jan is asked to make a desperate flight to safety with a young girl called Renate, his employer's German-Jewish daughter who has been offered shelter on a farm near the Belgian border. After a frightening drive across wartime Nazi Germany, Jan eventually reaches England.

Following specialist military training, he undertakes two missions: first with the partisans in Poland and then rejoining Renate to report on the build-up of German forces behind the Western front.

In a dramatic climax, Jan and Renate are captured by the Gestapo and must escape in order to be smuggled across the border to Belgium and England.