Antonio Bonocore, caretaker of a building in Rome with a German wife, is to attend the passing of Mr. Andrea, an elderly tenant who, before dying, tells him to be in possession of a suitcase inside with a few original clichés of the Bank of Italy, of which he had long been an employee, and the watermarked paper to print the 10,000 liras banknote.

Bonocore, however, is going through a bad time: basically an honest person, has refused to become an accomplice of accountant Casoria, the new administrator of the condominium, which had proposed to make a series of fraudulent transactions against the same building, and for this reason is under threat of dismissal.

Thus he decides not to destroy the bag but, ignoring the banknote printing techniques, to produce 10,000 notes is forced to ask the cooperation of the typographer Giuseppe Lo Turco (The Turk) and, later, the painter Cardone, both with economic problems.

The three manage to print banknotes and "split" in a tobacconist one night, but things get complicated when Bonocore discovers that his eldest son Michele, a brilliant revenue officer recently moved to Rome, is following its own delicate investigation on a batch of counterfeit notes.

The three, now at peace with themselves, decide to destroy all counterfeit notes and the suitcase with the clichés, setting up a bonfire: as a final gag, Bonocore realises (too late) that he threw into the flames, in the hurry, even the envelope containing his salary.