Henri “Papillon” Charrière, a safecracker from the Parisian underworld, is wrongfully convicted and sentenced to life imprisonment in the penal colony of French Guiana, where he forges a strong friendship with Louis Dega, a counterfeiter who needs his protection.

When ex-con artist Harry claims that a secret treasure is hidden inside Candleshoe, an English estate, he creates an elaborate plan to find and steal the prize. By convincing a girl named Casey to impersonate the estate owner's long-lost granddaughter, Harry hopes to uncover the treasure's location. But when Casey has a change of heart, she must follow the clues and find the treasure, in order to save Candleshoe and stop Harry before it is too late.

Robin Hood, aging none too gracefully, returns exhausted from the Crusades to woo and win Maid Marian one last time.