From visionary anime auteur Masaaki Yuasa comes a joyously hallucinogenic but family-friendly take on the classic fairy tale about a little mermaid who comes ashore to join a middle-school rock band and propel them to fame. Kai, a young middle schooler, lives in a lonely fishing village, with his father and his grandfather. He used to live in Tokyo, but after his parents divorced he moved back to his parent’s home town. Kai is lonely and pessimistic about his school life. One of his joy is uploading songs he writes to the internet. One day, he meets Lu, who sings merrily and dances innocently to his music. As Kai spends more time with Lu, he finds he is able to tell her what he is really thinking, and a bond begins to form. But since ancient times, the people in the village have believed that mermaids bring disaster and soon there is trouble between Lu and the townspeople, putting the town in grave danger.