Haru Yoshioka, a high school student, is tired with the routine of life. She saves Prince Lune of the Cat Kingdom from being driven over by a vehicle one day. As a thank you, the Cat King gives her "gifts" and invites her to the Cat Kingdom to marry Lune. Haru's failure to communicate effectively with the cats leads to the mistaken belief that she has accepted the proposal. As Haru mulls over how to get out of this situation, a mysterious voice advises her to look find the Cat Bureau. However, not long after she arrives at the Cat Bureau, a swarm of cats swoops in and forcibly transports her to the Cat Kingdom, along with a member of the Cat Bureau. worried about their safety, owner of the Cat Bureau, Baron Humbert von Gikkingen, follows close behind.