Deanna Durbin plays Constance Harding, a poor little waif who goes to live with rich relatives. Most of her snobbish new family are appalled by her. She's neglected, unloved and left out of all the glittering events the family attends. However, come the night of a fabulous society ball, she's determined not be left out again! With the help of the family servants, she is transformed into a society princess and attends in secret.
At the ball, she meets charming young socialite Ted Drake (Robert Stack, in his first screen role), and the couple fall in love. On the stroke of midnight, she quickly returns home, leaving only her shoe behind. Now Deanna's spiteful relatives convince her that Ted was only toying with her affections. He could never love a poor girl such as she...could he?