High school student Haru Yoshioka is bored with the monotony of life. One day, she saves Prince Lune of the Cat Kingdom from being run over by a truck. As a token of gratitude, the Cat King sends her "presents" and invites her to the Cat Kingdom to become Lune's wife. Haru's inability to properly communicate with the cats leads to the misunderstanding that she has accepted the proposal. As Haru ponders on ways to escape the predicament, a mysterious voice instructs her to search for the Cat Bureau. However, not long after she finally arrives at the bureau, a horde of cats swarms in and forcibly takes her to the Cat Kingdom, along with a member of the Cat Bureau. Concerned for their safety, owner of the Cat Bureau, Baron Humbert von Gikkingen, follows close behind. The more Haru immerses herself in the activities of the Cat Kingdom, the more cat-like she becomes. To her dismay, she soon learns that, unless she can find her true self, she may become a cat permanently. Haru's adventures in the world of cats lead her down a path to self-discovery, allowing her to return as a more confident person. The main character of the story is Haru. Haru is a clueless, ordinary 17 year-old girl. She has no special abilities and neither is she an extraordinary beauty. When faced with reality, she is unable to make decisions for herself, thus often swaying to others' opinions to avoid challenge. One day, Haru saved the life of a cat without consideration of her own safety. The cat turned out to be the Cat Prince from the Kingdom of Cats, however as a result, Haru is trapped in the world of cats. Can Baron and Muta rescue Haru who has wandered in the world of cats?