Yuku is a young mouse who lives with her fam­i­ly in the cel­lar of a cas­tle. Her grand­moth­er pass­es on the fam­i­ly val­ues by telling her time­less folk tales. Injured in a tus­sle with a cat, the old mouse is bedrid­den and she tells her chil­dren that she will have to leave them to fol­low the lit­tle blind mole into the Earth’s tun­nels. In one of her grandmother’s sto­ry­books, Yuku learns that the flower of the Himalayas can bring her eter­nal light. She leaves on a jour­ney of dis­cov­ery to find the flower.