It is the summer of 1939. A young Oxford don, Richard Myles and his wife Frances are about to leave for their usual long vacation on the continent. At the request of a Foreign Office friend of Richard's they agree to serve as messengers to a man who has been involved in rescue work and anti-Nazi espionage, a man who now seems to have gone missing. Their qualifications? Next to nothing except for Richard's superb memory and the fact that they look so very innocent. Across a continent on the brink of war from Paris to Innsbruck and beyond Richard and Francis travel ever deeper into danger.