Heidi lives with her grandfather in the Swiss Alps in the summer, and she and Peter play and tend the goats. In the winter, she stays with Peter's mother, and she and Peter attend school. One day a letter arrives from Heidi's friend Klara Sesemann, an ill youngster who spends most of her time in wheelchair, stating that she is coming to visit. The teacher has been having trouble getting Peter to study, and Heidi's grandfather decides to pose as Santa Claus and scare him into it. This is successful, and Heidi helps Peter learn to read. they attend school. The arrival of summer also brings Klara, with her grandmother and her prim governess Rottenmeyer. Heidi's grandfather suggests that Frau Sesemann stay with him and Heidi, while Rottermeyer stays in the village to visit and keep an eye on Klara. Peter is resentful and destroys Klara's wheelchair. Heidi's grandfather is secretly pleased, as he feels that Klara doesn't really need it. Calamity strikes when a storm causes the brook to overflow, flooding the village and wrecking many houses. Klara pitches in to help and forgets about her illness, emerging a healthy and happy girl. Her father is overjoyed and organizes a festival in a nearby town to help the stricken village.