The orphan Heidi is five years old when her aunt Dete takes her to her grandfather in the Swiss mountains. The grumpy old man, who everyone just calls Alm-Öhi and who lives in seclusion on his mountain pasture, initially has nothing to do with his granddaughter. But over time, he takes his granddaughter to heart and Heidi becomes a real child of the mountains.
Soon she is looking after the goats together with her new friend, Goatherd Peter. Heidi loves all animals, but especially the little goat Schnucki, her bird Pieple and finally even Joseph the St. Bernard. But one day, Aunt Dete returns and takes Heidi with her to Frankfurt...