Memoru belongs to a group of 245 beings who arrived on Earth after their vessel from the Riruru Star suffered an emergency crash landing. Their bodies are so minuscule that they could rest on a human palm. One day she hears enchanting music, follows its source, and discovers an enormous house she had never seen before, where a girl taller than herself plays the piano. Memoru returns secretly with her companions Popitu, Rupangu, and Pi, but the human girl, Marielle, appears ill and on the brink of death. Moved by sorrow, Memoru lets her tears touch Marielle's lips; the girl recovers and a deep friendship blossoms between them.