The sound of horses' hooves and a cracking whip is heard. A stranger arrives, asking the way to the castle. Lisa points out that it is getting late and he will not reach it before dark and she offers him lodging at her inn. When he says that he knows the inn, all are surprised. (Rodolfo's aria: / "O lovely scenes, again I see you, / where in serenity I spent the calm and happy days of my earliest youth".) The newcomer, who surprises the villagers by his familiarity with the locality, asks about the celebrations and admires Amina, who reminds him of a girl he had loved long ago. ( / "You can't know how those dear eyes gently touch my heart, what adorable beauty".) He admits to having once stayed in the castle, whose lord has been dead for four years. When Teresa explains that his son had vanished some years previously, the stranger assures them that he is alive and will return. As darkness approaches the villagers warn him that it is time to be indoors to avoid the village phantom: / "When the sky is dark at night, and the moon's rays are weak, at the gloomy thunder's sound [...] a shade appears." Not being superstitious, he assures them that they will soon be free of the apparition. Elvino is jealous of the stranger's admiration of Amina; he is jealous even of the breezes that caress her, but he promises her he will reform. (Duet finale, Elvino and Amina: / "I envy the wandering breeze that plays with your hair, your veil..")