Heidi lost her parents when she was young, so she was taken care of by her aunt. Later, because her aunt had to work outside, Heidi went to live with her grandfather who lived in the Alps. Her grandfather had a strange temper and didn't get along with the villagers. He had been living alone in a wooden house in the mountains for a long time. When Heidi came to her grandfather's house, her innocence and straightforwardness finally melted her grandfather's heart. Here Heidi also made a new friend - the shepherd boy Peter. They wandered among the mountains and green fields together and lived a leisurely and happy life. But later Heidi was forced to leave the mountains and was sent to Frankfurt to be the playmate of a rich girl named Clara who couldn't walk. Facing the big girl with a strange temper, how could Heidi continue to infect others with her optimism? When could she return to the Alps to reunite with her grandfather and Peter again?