Miyo Sasaki is a 14-year-old girl living in Tokoname, Japan. She sports messy light brown hair, often tied in a messy ponytail, and has light brown eyes. Her school uniform is typically disheveled, with her polo shirt partially untucked, reflecting her inner turmoil. Her background involves significant familial trauma. Her biological mother abandoned the family, leading Miyo to resent her father's new partner, Kaoru Mizutani. She formally addressed her as "Ms. Kaoru," rejecting her attempts to integrate. This estrangement extended to Kaoru's cat, Kinako, whom Miyo perceived as cold. The family separation and changes contributed to her emotional struggles, including teasing during elementary school. Personality-wise, Miyo projects a cheerful, rambunctious facade marked by bold expressions of emotion and persistent romantic advances toward her classmate, Kento Hinode. Her overt attentiveness includes a distinctive "Hinode Sunshine Attack," bumping into him from behind. However, this exuberance masks deep-seated insecurities and a tendency to suppress negative emotions. When overwhelmed, she perceives disliked people as "scarecrows," emotionally distancing herself, a coping mechanism stemming from unresolved trauma and fear of abandonment. A pivotal moment occurs during a local shrine festival when Miyo encounters a mysterious Mask Seller on a bridge. He gives her a magical Noh mask enabling transformation into a white cat with blue eyes and light brown fur accents around the nose and tail tip. In this feline form, named "Tarō" by Hinode after his deceased dog, Miyo visits him regularly. As Tarō, she listens to his personal concerns, including his family's decision to close their pottery shop due to financial constraints, and witnesses his affection for the cat—a stark contrast to his rejection of her human self. Miyo's dual existence creates conflict. She yearns to confess her identity as Tarō but fears Hinode's rejection. After overhearing classmates insult him, she impulsively defends him, resulting in injury. His subsequent kindness—taking her to the nurse and sharing lunch—briefly bridges their human connection. This, combined with learning about the pottery shop's closure, motivates Miyo to write a heartfelt confession letter. However, bullies intercept and publicly humiliate her by reading it aloud. Hinode, embarrassed, coldly states he hates "pushy people like her" and explicitly declares he hates her. Devastated, Miyo decides perpetual life as Tarō is preferable to human rejection. She relinquishes her human face to the Mask Seller, becoming fully feline and disappearing from human society. Trapped as a cat, she overhears Hinode express regret over his harsh words and realizes she misses her human life. Regret intensifies as she loses the ability to understand human speech and observes Kinako temporarily assume her human form using the mask to extend her lifespan for Kaoru. To reclaim her humanity, Miyo pursues the Mask Seller to a mystical Cat Island, encountering other humans who permanently transformed and now regret it. With Kinako's assistance, Hinode learns the truth and acquires a cat mask. His partial transformation into a hybrid cat-human enables him to reach the island. After a confrontation where the Mask Seller attempts to finalize Miyo's transformation by extracting her lifespan, intervention from resentful transformed cats and Hinode's sincere apology leads to resolution. Hinode confesses his reciprocal feelings, and Miyo retrieves her human face. Following these events, Miyo undergoes significant development. She reconciles with Kaoru, evidenced by dropping the formal "Ms." honorific, and becomes more accepting of her family. She also improves her social interactions at school. Her emotional barriers and reliance on masks—both metaphorical and literal—diminish as she learns to confront problems directly and value genuine connection over escapism.