The aging villain Émile Morland talks his old friend Aristide into helping him with to kidnap the son of a millionaire. Moreover, Morland engages the young actress Amandine and borrows a child baptised Alberto from his acquaintance Tony. Morland's plan is to exchange the children and then to reveal this in order to retrieve ransom from millionaire Rifai. But to everybody's surprise Rifai prefers Alberto to his moody and wearisome own son. He refuses to pay ransom because he is now happy as it is.