Following the tragic loss of her mother in a car accident, nine-year-old Melmo Watari now confronts a major challenge: caring for her two younger brothers, preschooler Totoo and baby Touch. Observing from Heaven and worried about her children's dire circumstances, their mother decides to make one final appearance in their lives as a ghost, giving Melmo a jar filled with magical candies. These candies possess the power to age her by ten years or de-age her by the same amount, as well as transform her into any animal she chooses. Utilizing these new abilities, Melmo adopts various disguises as a 19-year-old woman to look after her brothers, all while attempting to maintain a normal life.