The first scene takes place at the Nonnberg Abbey in Austria in 1938. The nuns are pursuing their respective tasks, but the postulant Maria is not with them, for she is lying in a hammock on the mountain-top enjoying the beauty of Nature (“The Sound of Music”). The nuns, and the Mother Abbess particularly, are considerably disturbed about her, since they are convinced she is not ready to enter upon a life dedicated solely to religion (“Maria”). The Mother Abbess confesses that there are many pleasures in life which she shares with Maria (“My Favorite Things”), but for Maria’s sake she decides to send the postulant away to serve as temporary governess for the seven children of Captain Georg von Trapp, a retured Austrian Naval officer, and a widower.
Maria comes to this household and completely wins over the children’s affection, particularly after she entertains them and allays their fears during a thunderstorm (“The Lonely Goatherd”). She teaches the children to love music, and especially to sing (“Do, Re, Me”). And she can be uniquely sympathetic to the oldest of the children, Liesl, when she gets involved in her first love affair, with the village boy, Rolf Gruber (“Sixteen Going on Seventeen”).
The Captain brings from Vienna Elsa Schraeder, his fiancée, who prevails on him to give a huge party. After the children bid the guests good night (“So Long, Farewell”), Maria becomes suddenly aware that she has fallen in love with her employer. Horrified, she flees from the villa back to the Abbey, where the Mother Abbess encourages her to overcome any obstacle that may lie in the way of her happiness (“Climb Every Mountain”). Returning to the villa, she finds that the Captain and his fiancée have separated following a quarrel over Nazism. The romance of Maria and the Captain now develops rapidly. They get married in a festive ceremony at the Abbey. After returning from their honeymoon, the Nazis–who by now have invaded Austria–summon the Captain back to naval duty. An avowed anti-Fascist, the Captain resolutely refuses to do so. He arranges to flee from the villa with his wife and children. With the Nazis in pursuit, the Trapps hide in the garden of the Abbey, and after that make their way to freedom by foot over the mountains.