Haru Yoshioka is a shy but noble high school student who carries a quiet, almost magical ability to talk with cats. When she bravely saves a cat from a speeding truck, she discovers that the rescued feline is Lune, the Prince of the Cat Kingdom, a revelation that pulls her from the ordinary into a realm of whimsy and danger. The cats shower Haru with curious gifts—catnip and mice—along with an offer that would bind her to the Prince. Her reaction is cautious, and her mixed reply is interpreted as an acceptance.
To avoid an arranged fate, Haru follows a mysterious, kindly voice that guides her to seek out Muta, a large white cat who becomes her guide. Muta leads her to the Cat Bureau where she meets Baron Humbert von Gikkingen, a living feline statue brought to life by artistry, and Toto, a stone raven who shares in the magic and danger of this new world. Before long, Haru and Muta are whisked away toward the Cat Kingdom, while Toto and Baron stay behind to track them from the skies. The entrance to this otherworldly land lies beneath Earth’s surface—five lakes arranged as a cat’s paw, a cryptic gateway to a realm where cats rule and humans are guests.
Inside the Cat Kingdom, Haru is treated to a grand feast in the castle of the Cat King. She begins to transform—fangs, whiskers, a tan tail and paws emerging as her humanity and feline nature blur into one. The King hopes to forge a union between Haru and the Prince, turning romance into political alliance. At the feast, Baron (in disguise) dances with Haru and speaks a warning: the more she loses herself to the kingdom, the more cat-like she will become, and she must find the belief in herself to choose her own path. When Baron is discovered and must defend them, he is aided by Yuki, a cat maiden who had previously warned Haru to leave. She reveals an exit tunnel, guiding Haru, Baron, and Muta through a maze to a tower that houses a portal back to Haru’s world. The King intensifies his schemes to keep them, intending to make Haru his daughter-in-law rather than allowing her a return.
The situation shifts when Prince Lune and his guards return, exposing that the King was not acting on the Prince’s behalf and that Lune himself plans a separate proposal to Yuki. A startling revelation follows: Muta is Renaldo Moon, a notorious criminal in the Kingdom who once devoured an entire lake of fish in a single sitting. Haru learns that the strange voice urging her toward the Cat Bureau belonged to Yuki. In a poignant moment, Haru remembers how she once shared fish crackers with Yuki as a child, a debt repaid in kindness and friendship. After Haru rejects the King’s marriage proposal, Muta tells her, “I respect a woman who stands up for herself,” and helps them slip away from the King’s soldiers.
With the aid of Prince Lune and Toto, Haru, Muta, and Baron escape the Cat Kingdom and return to the human world, Haru stepping back into her life with a strengthened sense of self. Her friend Hiromi fills her in on the changing dynamics of her social circle, including the breakup of her former crush, and Haru responds with quiet resolve: the past no longer holds sway over her. > It doesn’t matter anymore.
