A girl with nothing special about her gets pulled into a cat kingdom where the rules don't make sense and the stakes are absurd. You spend the whole movie watching her figure out how to survive on stubbornness and bad decisions, which somehow works. The backgrounds are painted like someone's half-remembered dream of a place that never existed, the pacing never rushes, and it feels less like a story and more like time you get to spend somewhere safe.

Haru is an ordinary seventeen-year-old high school girl who drifts through a dull routine and tends to go along with what others think rather than make her own decisions. That changes when she saves a cat from being hit by a truck without a thought for her own safety. The cat turns out to be Prince Lune of the Cat Kingdom. In thanks, the Cat King sends her odd gifts and invites her to marry the prince, and because Haru cannot make herself understood, the cats believe she has said yes. Guided by a mysterious voice, she seeks out the Cat Bureau, only to be carried off to the Cat Kingdom by a swarm of cats. Baron Humbert von Gikkingen, the bureau's owner, follows to help. The longer Haru stays, the more cat-like she grows, and unless she can find her true self, the change may become permanent. Blending fantasy, comedy, adventure and drama, the film is a loose spin-off of Whisper of the Heart that brings back Muta and the Baron.