In the middle of the day, on a busy street, young Haru bravely pulls a charming cat out from under a truck. To her great surprise, the cat stands on its hind legs and thanks Haru in human language. It turns out that the cat is the prince of the mysterious Cat Kingdom, and the Cat King wants to marry him to the brave rescuer. Soon, Haru is kidnapped, but she doesn't want to be a cat princess, and only her loyal friends, the fat vagabond Muta and the magnificent Baron, can rescue her from the cat's captivity.