Hanley is pulled off the line and sent to London. He discovers that he is to be used in a secret mission to aid a French physicist to escape occupied France before the Gestapo captures him. Hanley and the man's son were friends in college and Hanley spent one summer in France at the family's home. Hanley is the only man the scientist will trust, especially since it has been discovered that someone in the French resistance who is helping them is a double agent.