The narrative opens with the transition from a "long winter" to the vibrancy of May, a season that brings profound change to the lives of the characters. Heidi’s influence on Peter is particularly noteworthy, as she has helped him "learn to read quite well," granting Grandmother the daily joy of hearing a hymn. This period of personal development encourages Peter to attend school more "regularly," signaling a shift in his character. As the "first signs of spring appeared," Heidi and Grandfather return to their mountain home, preparing for the arrival of their long-awaited guests from Frankfurt: Clara and Grandmama.
The anticipation builds until finally, a "strange-looking parade" emerges, making its way up the mountain. The procession is a spectacle, featuring men carrying a chair with a "girl wrapped in shawls," a woman on horseback, and a gentleman burdened with a massive "bundle of shawls and furs." Despite the unconventional arrival, the reunion is immediate and heartwarming. Heidi, shouting "Here they come!" in her excitement, facilitates the introduction between her visitors and Grandfather. The group quickly bonds, transitioning into what feels like "old friends" while sharing a meal of "milk and toasted cheese."
The mountain environment acts as a catalyst for Clara’s well-being. Grandmama observes with surprise that Clara is "taking a second piece of toasted cheese," noting that it tastes better than anything at home. Grandfather astutely attributes this improvement to the "mountain air," suggesting that "everything seems better here." The atmosphere of the hut, particularly Heidi’s "pleasant, cheerful bedroom" where one can "look straight into the sky," leaves a lasting impression on Grandmama. Recognizing the potential for Clara’s health, Grandfather proposes that "Clara might remain up here," promising that they would "look after her well." This offer is met with deep gratitude from Grandmama, who thanks him with her "whole heart."
The final section of the narrative focuses on the emotional and spiritual impact of the mountain on the children. After Grandmama departs, the girls prepare for their first night in the hayloft. Clara is struck by the beauty of the "shining cluster of stars" visible through the window, remarking that it feels as if they are "going to drive straight into heaven." Heidi’s response—that the stars "twinkle because they live up in heaven" and "nod at us because they want us to be happy too"—reflects her unwavering optimism and faith. Heidi reassures Clara that "God fixes everything" and that "all things will be fine in the end." This sentiment provides Clara with a sense of peace, allowing her to drift off to sleep while thanking God for the "wonder of the day," marking the beginning of a transformative chapter in her life.