Inspiring and insightful, this multi-layered drama revolves around Heidi, a young orphan who lives for several years with her Aunt Dete (Schinz). Later she is brought to live in the mountains with her elderly grandfather Alpöhi (Ganz).
Despite being known as a fearsome and hermit like character he soon learns to love Heidi. She quickly makes friends with goatherd Peter (Agrippi), a boy just a little older than her. For the next few years Heidi grows up happily with her grandfather and Peter, although she is sometimes unhappy that she cannot go into the village to school, especially in winter when Peter does not look after the goats.
Some time later Aunt Dete returns and tricks Heidi into running away with her to Frankfurt to become a companion to a young girl Klara (Ottmann) in an upper-class family townhouse. Klara uses a wheelchair and lost her mother at an early age. Although her father loves her he is away on business a lot and she is left with her strict governess Fräulein Rottenmeier (Schüttler). It takes Heidi a very long time to fit into polite society but she forms a bond with Klara and learns to read. In the end though the desire to go back to the open spaces of the mountains becomes too strong for a homesick Heidi and Klara's father returns her to her grandfather, much to Klara's grief.
Heidi settles back into mountain life with her Grandfather and Peter but writes to Klara a lot. In the end Klara's grandmother allows her to visit Heidi in the mountains. There Heidi and Klara re-connect, initially to the annoyance of Peter who ruins her wheelchair. However without the chair Klara realises that her paralysis is in her mind and was brought about by the loss of her mother. She then learns to walk before being taken home by her grateful father.
Heidi and her grandfather move to the village so Heidi can continue to learn to read and write, so she can achieve her dream of being an author. It is implied that she and Peter remain good friends and that she and Klara see each other on a regular basis.