When Claude Peri and Madeleine Bayard meet in Indochina in the 1930s, they fall immediately and passionately in love. They are soulmates, and not only lovers: each works as a spy for the French government. Claude travels alone through Hitler's Germany (where he is invited to dinner with Hermann Goering), the Middle East, India and Thailand. Then, travelling together to Paris in 1939, Claude and Madeleine are appalled as they watch their countrymen flee the capital in terror as the German army advances.

Claude and Madeleine tells how, aboard their beloved ship Le Rhin, they abandon their allegiance to France and throw in their lot with the British. After mutiny, mistrust and seemingly impossible hardship, SS Le Rhin eventually becomes HMS Fidelity, running secret missions for the British navy.

Full of extraordinary stories and compelling characters, taking the reader from Hanoi to Calcutta, Europe and beyond, Claude and Madeleine combines social history, politics, travel and biography in an epic and tumultuous story which is by turns thrilling, revealing and deeply moving.