PLOT: Miyo Sasaki is an unhappy middle school girl living in the town of Tokoname who does not get along with her stepmother. Each day at school, she goes out of her way to flirt with her crush, Kento Hinode, in spite of his repeated rejections. One day, Miyo receives a magical Noh mask from a mysterious mask seller, which lets her become a cat. As "Tarō", she spends time with Hinode at his home, keeps him company while he studies Japanese pottery and listens to his problems. She longs to confess that the cat that he loves and the girl that he hates are the same person, but is afraid that he will reject her and refuse to visit with Tarō anymore.
One day, Miyo overhears a pair of boys at school speaking ill of Hinode, and loudly intervenes to defend his honor. She injures herself during the altercation, and for the first time, Hinode shows warmth to her as he takes her to the nurse's office and shares his lunch with her. Later that evening, as Tarō, Miyo learns that Hinode's family is closing their pottery shop, as his grandfather is retiring and the family can no longer afford it. Hinode's kindness towards her, combined with a need to cheer him up at the loss of his hobby inspires Miyo to confess her love in the form of a letter. The next day in class, a bully snatches the note before she can deliver it and reads it aloud, embarrassing both Miyo and Hinode. When confronted, Hinode saves face by publicly telling Miyo that he hates her. Miyo later visits Hinode as Tarō and spends the night with him. In the morning, she decides that life with Hinode as a cat is better than life without him as a human, and her human face falls off in the form of a porcelain mask. The mask seller appears to claim Miyo's face and tells her that he will give it to a cat who wants to become human. Miyo's friends and family begin searching for her, including Hinode, who confesses to Tarō that he doesn't really hate Miyo. Trapped in her cat body, Miyo begins losing her human faculties and regrets her choice. Kinako, the cat of Miyo's stepmom, obtains Miyo's human face from the mask seller and takes over her human life. Miyo implores her to return her face, but Kinako refuses, explaining that she is approaching the end of her natural lifespan but wishes to continue living and bringing happiness to her owner.
Miyo follows the shopkeeper to the secret Island of Cats where she hopes to convince him to turn her back into a human. Meanwhile, Kinako comes to understand just how much Miyo's stepmom loved her cat and has a change of heart. She reveals the secret of the masks to Hinode and takes him to the Island to save Miyo before her transformation becomes permanent. Kinako gives Hinode a cat mask, which turns him into a half-cat. Kinoko and Hinode are trapped by the masked seller but are rescued by Miyo and another cat who used to be a human. When Kinoko is about to give Miyo her face back, the mask stealer takes Miyo.
While Hinode eventually finds Miyo, the shopkeeper takes them to the "promised place" and attempts to finalize Miyo's and Hinode's transformation and extract their lifespan, but is foiled by all of the resentful humans that he had previously turned into cats. As they travel back to the human world, Miyo and Hinode confess their love to each other and Kinako returns Miyo's face, returning her to normal.