Heidi is taken to her grandfather's house by her Aunt Dete.

Heidi joyfully gets accustomed to her new surroundings.

Heidi goes with Peter, the local goatherd, to the pastures and enjoys a day of fun-filled picnic there.

While out on the pastures one day, Heidi encounters a storm. After braving it, she finds a nestling and decides to raise it.

Pichi is taken by Heidi to the mountain pastures and has another thrillingly exciting day filled with dangers. Meanwhile, through Peter, Alm-Uncle receives a letter from Aunt Dete, intending to take Heidi to Frankfurt, which he destroys, acting as if it does not concern him.

One day, in her attempts to learn how to be a goatherd, Heidi tries milking a goat and whistling, eventually succeeding.

With high winds in the mountain pastures, Alm-Uncle decides not to let Heidi go to the mountains. Instead, she helps her grandfather make cheese. But Snowflake, a baby goat, comes to her anyway, leading her to unintentionally ruin the cheese.

Pichi follows the seasonal birds, and Heidi finds it hard to calm down. Alm-Uncle takes her to collect chestnuts and grapes. Meanwhile, to make up for a previous quarrel, Peter captures a bird that looks like Pichi and gives it to Heidi. Heidi releases it and gives chestnuts and grapes to Peter to make up.

Winter arrives, bringing long hours indoors. Heidi arranges food under the cover of the three fir trees for herbivores and tries to befriend the animals.

After the snowfall ceases, Heidi is taken by her grandfather on a sled to Peter's grandmother, as per her invitation. There, Heidi learns of the grandmother's blindness and cries. She asks her grandfather to repair Peter's dilapidated home so the blind grandmother can find comfort.

Hunters try to get the herbivores Heidi feeds but are stopped. Later, Heidi sends Alm-Uncle to rescue the hunters after they venture out again. After much worry, Grandpa returns with them safely.

With spring arriving in the mountains, there are dangers of sudden avalanches. On returning from a sled race after giving Peter's grandmother a spring flower, they encounter an avalanche. Thanks to Alm-Uncle's quick action, they are saved instantly.

With spring officially back, Peter and Heidi return to the meadows with their flock. Peter gets into a fight with another herder who accuses him of trying to steal his stranded goat. Joseph's intimidating presence scares the individual off.

Heidi's favorite goat, Snowflake, is about to be sent to the slaughterhouse because it stopped giving milk. Heidi attempts to prevent this by gathering nutritional herbs from mountain crevices.

Mr. Strahl, the owner of Snowflake, is convinced not to slaughter the goat after Heidi demonstrates its increased milk yield.

Heidi visits Dorfli to check on Snowflake. On returning, she talks to Alm-Uncle about going to school, but he flatly refuses.

The local church pastor tries to convince Alm-Uncle to let Heidi attend school but is refused. Then Aunt Dete arrives, unwilling to accept no for an answer.

After threatening legal action, Alm-Uncle angrily allows Heidi to go with Dete to Frankfurt, despite protests from Peter and her grandmother. Heidi goes, unaware that Dete lied about it being a day trip.

Through coaxing, forcing, and lying, Dete takes Heidi to Frankfurt, where she becomes the playmate of an invalid child, Clara. Upon arrival, she is introduced to the governess Rottenmeier, who is strict, and Dete leaves.

After a sleepy dinner, Heidi’s life in Frankfurt begins. She is constantly nagged by Rottenmeier and disappointed when she sees that the window blinds do not show the mountains. She endures it to bring tobacco and white bread to her grandmother and grandfather.

During lessons and punishments, Heidi empathizes with Clara’s condition through her pet caged bird, which Clara also owns.

Heidi, avoiding Rottenmeier's gaze, explores the city but finds only a dreary urban landscape.

Heidi receives a kitten from the kind church tower maintainer and hides it in the attic with the help of the manservant Sebastian. Other kittens sent to her are promptly returned because Rottenmeier cannot handle them, along with a turtle that came from a street musician boy.

Rottenmeier discovers the hidden kitten and throws it away. Heidi leaves, but Sebastian assures her that the kitten is safe at a friend's house.

On a routine inspection, Rottenmeier finds all the white bread Heidi stored for Peter’s grandmother and confiscates it. Heidi wails, but Clara consoles her by saying the bread was already molded and cheering her up with a fairy tale.

Mr. Sesemann returns to visit Clara and is impressed with Heidi’s companionship with her. He later informs Clara’s grandmother, which annoys Rottenmeier but delights Heidi.

Clara’s grandmother becomes an instant favorite of both girls and spends a fun-filled day with them. For once, Heidi does not think about the mountains.

After seeing Heidi cry over a picture of the mountains, the grandmother takes both girls for a picnic in a state park, much to Rottenmeier’s chagrin.

After a day at the park, Clara falls ill.

To cure Clara, Heidi returns to the park to gather sunshine, butterflies, and flowers, which improves her condition.

Grandmother leaves after a mock wedding party, returning Heidi to her dreary city life.

Heidi is torn between wanting to leave her confined situation and not abandoning lonely Clara, when a nightly ghost appears in the Sesemann mansion.

Everyone is frightened by the ghost, but no one realizes it is Heidi sleepwalking, stressed and longing for the Alps. The doctor discovers this and convinces Mr. Sesemann and Clara, resolving the situation.

Heidi returns to the Alps and is reunited with her grandfather, wearing the same clothes she had when she was five.

Heidi relives all the experiences she missed while in Frankfurt.

Heidi spends an adventure-filled day with Peter and the goats, including discovering a new mountain-top lake.

Heidi begins writing letters to Clara and reading hymn books to Peter’s grandmother. Alm-Uncle decides to repair a rundown house in Dorfli so Heidi can conveniently attend school in winter.

On the first day of winter school, Peter does not attend as he is running an errand for a Dorfli resident.

During a sled race, Peter competes using his carpentry skills and finishes jointly in first place, splitting the prize.

Clara insists on visiting the Alps to see Heidi. Mr. Sesemann arranges for a doctor to evaluate whether the Alps are suitable for Clara’s health.

The doctor visits the Alps. Heidi shows him the mountains, and although he doubts the terrain is suitable for Clara, he is persuaded by her plea.

Heidi prepares the Dorfli winter home for Clara, who receives a warm welcome.

Clara is enchanted by the mountainside and wishes to stay in Heidi’s hut. Her wish is granted, much to Rottenmeier’s annoyance.

After skipping lessons and enjoying the mountain soil, Clara asks Heidi for mountain flowers. Together, they plan a picnic on the mountain.

Peter tries to carry Clara up the mountain using his spare pants, but it is too strenuous for him, so he looks for alternatives.

Clara enjoys her days in the mountains with Heidi and Peter, braving a mountain shower and reading to Peter’s blind grandmother.

Clara’s grandmother visits and immediately sends Rottenmeier away, enjoying time with Heidi and Clara.

Clara shows promising signs of standing up, though not fully consciously. Her grandmother takes her to Heidi’s lake to encourage her.

Clara practices standing with Heidi’s help, though she remains uncertain. During the farewell party of Clara’s grandmother, school friends join the celebration, motivating Clara.

Clara attempts to stand using handrails, encouraged by Heidi.

Clara starts walking properly, surprising her father, Mr. Sesemann.

Clara leaves for treatment at Bad Ragaz. Heidi wonders when they will meet again to enjoy the Alps together.