Heidi, a young orphan girl living with her aunt in Frankfurt, is forced to move to the Swiss Alps to live with her ornery grandfather. At first, he resents her presence, but, after a short while, Heidi manages to pierce his gruff exterior, and the two become close. She also befriends a young shepherd named Peter. After three years, Heidi's aunt arrives and demands Heidi's return to Frankfurt.

Heidi lives with Alp-Öhi n the Swiss Alps in the summer, where she helps Peter tend the goats. In winter, she stays in the village and attends school. One day, a letter arrives from Heidi's German friend, Klara Sesemann, announcing her visit. Klara indeed appears the next summer along with her grandmother and the prim governess Miss Rottenmeyer. Klara is quickly convinced to stay with Heidi, but Peter becomes resentful that Heidi now spends so little time with him...