When Heidi, a cheerful 5-year-old orphan, comes to live with her grandfather in the Swiss Alps, she brings a bright ray of sunshine into the lives of the people around her. Young Peter, a goatherd, shares her love of nature, and his blind grandmother delights in the little girl's bubbling personality. Even Heidi's surly and hermit-like grandfather, the old Alm-Uncle, finds his long-lost grandchild a source of immense pleasure.

A few years later, when she is forced to go to Frankfurt to serve as a companion for Clara, she is a sickly girl, Heidi must leave her beloved mountains and friends behind an experience that proves highly traumatic to the innocent and sensitive little girl.