Miyo “Muge” Sasaki is a peculiar second-year junior high student who has fallen in love with her classmate Kento Hinode. Muge resolutely pursues Kento every day, but he takes no notice of her. Nevertheless, while carrying a secret she can tell no one, Muge continues to pursue Kento. Muge discovers a magic mask that allows her to transform into a cat named Tarō. The magic lets Muge get close to Kento, but eventually it may also make her unable to transform back to a human.

Dueling cat-and-mouse team Tom and Jerry hit the high seas on a hunt for buried treasure in this pirate adventure. The tale begins when crew member Tom sets sail with an infamous pirate and finds a treasure map along with stowaway Jerry. The furry swashbucklers race to a deserted island where X marks the spot, but along with battling each other, they must outwit ruthless buccaneers, angry monkeys and a giant octopus to strike it rich.