A collaborator has cost the lives of several allied agents, in Vichi France, early in World War two, by informing on new arrivals in that area to the Germans. John, a Franco-American boy, hears about this, and proposes a very unorthodox proposition; that a teenage boy, fluent in French, and posing as a war orphan, would not be suspected an agent by either the Germans or the traitor. He assumes the identity of Jean Pierre Lemaire, a boy injured in a bombing in Liege Belgium, having a French father and a German mother, and is being repatriated to France. The book covers John's acceptance, training, and activities, with the French Resistance in France and the boy's German relatives in Germany.