The World Tree, which provides energy for all plants, is on the verge of withering. The little sheep shrink themselves and embark on a journey aboard the Hip-Hop Train to save the great tree. Along the way, a single raindrop or a fallen leaf becomes a huge obstacle for the miniaturized sheep. On top of that, they must constantly fend off the harassing Gray Wolf. However, undeterred by the dangers, they rely on their wit and courage to overcome each crisis, befriending a host of insect companions along the way. Ultimately, they succeed in their mission, revitalizing the World Tree and restoring it to life.