Childhood friends Tommy and Tuppence 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
Jiro, an ex-convict, comes back to the street after eight years. The gang to which he belonged is nearly disbanded; only the aging boss in his sick bed remains. Still loyal to the ex-boss, Jiro approaches the powerful Hasama family to ask for assistance.
