Fourteen-year-old Nils Holgersson lives on a farm with his parents in southern Sweden's Scania region. He displays laziness, disobedience, and cruelty, tormenting animals for amusement. His neglect of responsibilities and mistreatment of farm creatures establish his initial selfishness. A pivotal encounter occurs when Nils captures a tomte, a magical gnome-like being. Rejecting the tomte's offer of a gold coin for freedom leads to Nils being shrunk to miniature size as punishment. This transformation grants him the ability to understand animal speech but makes him vulnerable to retaliation from the abused farm animals. To escape, he flees on the back of Morten, a farm goose joining migrating wild geese. Accompanied by his pet hamster Carrot—an addition unique to the anime—Nils travels across Sweden with the wild geese flock led by Akka of Kebnekaise. This journey forces dependence on animals he previously mistreated. Early interactions reveal lingering selfishness, like prioritizing his own needs during group challenges. However, repeated threats from the persistent fox Smirre, who stalks the geese across seasons, compel Nils to protect others. He devises strategies to thwart Smirre's attacks, showcasing emerging courage and ingenuity. Nils's development unfolds through episodic trials. He mediates animal conflicts, aids humans in distress—guiding lost children or assisting impoverished families—and intervenes in natural crises like floods or forest fires. These experiences foster empathy, responsibility, and selflessness. His bond with Morten deepens, evolving from mutual necessity to genuine loyalty, especially as Morten faces challenges integrating with wild geese and raising goslings. The curse's escape clause—reversion to human form upon proving moral improvement—drives Nils's internal struggle. His turning point arrives when he selflessly offers to remain small permanently to save Morten from sacrifice. This act of bravery fulfills the tomte's condition, restoring his original size upon returning home. The journey culminates in a transformed character: respectful toward nature, compassionate toward animals, and responsible toward community.