 Childhood friends Tommy and Tuppence (Prudence) meet in London after having served in World War I. Recently "demobed", short of money, and with no job prospects, they decide to become adventurers for hire. Soon, they are employed by the British Government to locate a secret treaty signed before the war. Bolsheviks, kidnappings, missing persons, and a marriage proposal for Tuppence, keep things moving for The Young Adventurers, Ltd.