A free-spirited nun is sent to work as the nanny for an Austrian baron's seven children and helps them to become a renowned singing group. The Baron is a good man, but he runs his family with the discipline of a drill sergeant. The former novitiate feels that children should be allowed to have fun and so teaches them to start enjoying life. She also encourages the talented septet to sing. When the Baron discovers his children acting frivolously, he is enraged. He is just about to fire her when he hears the sweet singing of his children. He keeps her on a little longer and even begins falling in love with her. But then she must return to her convent to renounce her vows. Later they are reunited and the family begins traveling and singing until the Nazis take over and the Trapp family is forced to flee to the U.S.