A young schoolgirl, Karin Kokubu, comes across a starving pig and feeds it an apple. The pig is in fact an alien being and a prince, and in gratitude he gifts Karin the ability to wield superpowers... as a pig. Karin is pleased at getting superpowers but is upset that she has to use them as a pig, but the prince explains if she can use her powers for good, she will collect a number of pearls, and with enough pearls she will earn the right to fight powers as her human form. Thus begins Karin's superhero life as the Pig Girl, Tonde Buurin.