A boy who deserves punishment gets it, then spends a year learning why cruelty matters by becoming small enough to be crushed by it. Every step north costs him something, comfort, certainty, the right to be selfish, until the person he becomes is unrecognizable from the person he was. Nils doesn't break the spell by finding Lapland. He breaks it by becoming someone the spell no longer fits.

Nils Holgersson is a selfish, troublemaking boy who torments everyone around him: his parents, the farm animals, and even a tiny creature called a tomte. When he captures the tomte, the magical being shrinks him down to miniature size as punishment. Now Nils can only reverse the spell by traveling across Sweden to distant Lapland, a journey he makes riding on the back of Morten, the farm goose, alongside a hamster named Carrot and a flock of wild geese led by the stern but caring Captain Akka. The road north is dangerous and strange. Nils encounters cruel witches, talking statues, wise ravens, and one fox that refuses to give up the chase. As the journey goes on, Nils begins to change, finding a kind heart and a love for nature he never showed at home. Yet when the time comes, he must choose between his human family and his feathered friends.