On Luisa's birthday, the villagers have gathered outside her house to serenade her. She loves Carlo, a young man she has met in the village ("Lo vidi e 'l primo palpito" /"I saw him and my heart felt its first thrill of love") and looks for him in the crowd. Luisa's father, Miller, is worried by this mysterious love since Carlo is a stranger. Carlo appears and the couple sing of their love (Duet: "t'amo d'amor ch'esprimere" / "I love you with a love that words can only express badly"). As the villagers leave to enter the nearby church, Miller is approached by a courtier, Wurm, who is in love with Luisa and wishes to marry her. But Miller tells him that he will never make a decision against his daughter's will ("Sacra la scelta è d'un consorte" / "The choice of a husband is sacred"). Irritated by his reply, Wurm reveals to Miller that in reality Carlo is Rodolfo, Count Walter's son. Alone, Miller expresses his anger ("Ah fu giusto il mio sospetto" / "Ah! My suspicion was correct").