Tommy Beresford and Prudence Cowley, a young, destitute, and enamored couple, set out to start their own business after the devastation of World War I. Desperate for excitement and willing to undertake any task, they accept a mission from the enigmatic Mr. Whittington, that requires Tuppence to travel to Paris posing as the missing American, Jane Finn. However, the assignment turns treacherous when Tuppence's life is threatened, and her employer vanishes. Now, their task is to locate Jane Finn. With the help of an American millionaire and the British Intelligence, Tommy and Tuppence race against time to unmask the mysterious Mr. Brown and recover the vital documents.
