When Moomin wakes up early from his winter hibernation, he finds himself completely alone in an unknown world for the first time, as the Moomin valley has been covered by the icy veil of the Lady of the Cold. Initially searching for someone to take care of him and wanting to drive away the winter, the young Moomin embarks on a journey into the unknown. Through this tender adventure, he learns to create new friendships and to offer help to those who need it more than he does.