Jack Frost awakens from a frozen pond with amnesia. Upon realizing no one can see or hear him, he disappears. Three hundred years later, Jack, as the young Spirit of Winter, enjoys delivering snow days to school kids, but resents that they do not believe in him. At the North Pole, the Man in the Moon warns Nicholas St. North that Pitch Black is threatening the children of the world with his nightmares. He calls E. Aster Bunnymund, Sandy, and Tooth, to arms. They are then told that Jack Frost has been chosen to be a new Guardian. Visiting Tooth's world, Jack learns that each and every baby tooth contains childhood memories of the children who lost it, Jack's teeth included. However, Pitch raids Tooth's home, kidnapping all of her subordinate tooth fairies except Baby Tooth and stealing all the teeth, thus preventing Tooth from sharing Jack's memories and weakening children's belief in Tooth. In order to thwart Pitch's plan, the group decides to collect children's teeth.