A tale of thwarted love and mistaken and assumed identities, this comedy revolves around an ordinary man becoming ‘King for a Day’. Cavaliere di Belfiore has, to distract attention from the genuine monarch, assumed the identity of King Stanislas of Poland, and arrived with much pomp at the castle of Baron Kelbar near Brest. There he finds himself in the middle of preparations for two weddings: the baron's daughter Giulietta is, most unwillingly, to marry the elderly La Rocca, while a local military official is hoping for the hand of the Marchesa del Poggio. Can ‘King Stanislas’ use his regal power in time to disentangle these unhappy betrothals before his true identity is revealed?