Orphan girl Heidi spends the happiest days of her childhood together with her eccentric grandfather, cut off from the outside world in a simple cabin in the Swiss mountains. Together with her friend Peter, she tends to her grandfather's goats and enjoys freedom in the mountains to the fullest. But these carefree times come to an abrupt end when Heidi is taken to Frankfurt by her Aunt Dete to stay with the family of the wealthy Mr. Sesemann and be a playmate for his wheelchair-bound daughter Klara. Although the two girls soon become friends and Klara's grandmother awakens a passion for books in Heidi, Heidi's longing for her beloved mountains and her grandfather grows ever stronger.