La Sonnambula (The Sleepwalker) is a melodramma in two acts by Vincenzo Bellini written in 1831. The play centers around the coming marriage of the orphan Amina and a local farmer Elvino. Lisa, a villager who is also in love with Elvino is jealous of Amina, while at the same time rejecting the advances of Alessio, who is in love with her.
After a long absence, the lord of the village, Count Rodolpho, returns. Unrecognized because of his absence, he is entertained for the night by Lisa in her inn, but Amina walks in her sleep and wakes to find herself in the Count's room, arousing further jealousy in an already suspicious Elvino, who now rejects her, in spite of the attempted intervention of the villagers and the support of the Count...