One day the half-fairy Luuta runs into a new male student in school. She picks up a sparkling glass jar which he left behind. She starts to look for him and hears a tiny voice calling for her help. Follow its message, she slips into a secret alter realm and finds an injured boy knight fighting a monster by himself. She offers to form a pact with him and gains new powers. As news of more monsters spawn and invade numerous places, its up to Luuta to save her town.