One day, Nils, a mischievous boy who often picks on farm animals, upsets an old fairy. The angry fairy casts a spell on Nils and Carrot, his pet hamster, making their bodies smaller. When the animals see what has happened, they start to take revenge on him. To avoid the bullying, Nils and Carrot jump onto the neck of Molten, an earthbound farm goose who has dreamed of flying to the haven of migrant birds with wild geese. Ignoring the scorn of the wild geese, Molten, with Nils and Carrot on his neck, flaps his wings wildly...and with great effort takes off for the first time. With his new companions, Nils is about to start off on a spectacular adventure.
Nils and his pals are initially considered intruders by the wild geese, but slowly begin to obtain their trust. Nurturing friendships with Molten and Carrot, Nils starts to learn kindness, compassion, and other important lessons in life.