Jyunpei Kousaka is the main protagonist of the story and an ordinary second-year high school student. He lives with his mother and sister, who are both very fond of cats, a fact that complicates his daily life because he suffers from a severe allergy to them. This allergy is the root of his strong dislike for cats and anything related to them, making his home environment a constant source of discomfort.

His life takes an unexpected turn when he accidentally kicks a can that breaks the head of a cat deity statue. This act curses him with the ability to understand and communicate with cats. To lift the curse, he must perform one hundred good deeds or favors for cats; if he fails, he will be transformed into a cat himself, which, given his severe allergy, would likely be fatal. This supernatural predicament forms the core of his daily struggles. He must now secretly navigate the requests of the local felines while trying to maintain a normal high school life.

Personality wise, Jyunpei is often portrayed as a kind and caring individual, but he is also sarcastic and easily annoyed by the troublesome situation he finds himself in. Unlike many protagonists in similar stories, he is not depicted as perverted and is generally considerate of his friends' feelings. However, he can be indecisive and is notably insensitive, frequently failing to notice the romantic advances of the girls around him. His primary motivation for helping cats is not born from altruism but from the urgent need for self-preservation to avoid his cursed fate, and he often treats the cats' requests as a hassle.

Jyunpei has several key relationships that drive the story. He has a deep crush on his classmate, Kaede Mizuno, a girl who adores cats, which makes his attempts to get closer to her even more awkward given his allergy and secret curse. His childhood friend, Kanako Sumiyoshi, also plays a significant role, though their relationship is strained by a past misunderstanding. At home, he reluctantly takes guidance from the family's ill-tempered cat, Nyamsus. He also becomes entangled with other eccentric characters, such as his upperclassman Nagi Ichinose, the heir to a Yakuza family, and the twin sisters Kotone and Akari Kirishima, who are connected to the shrine where the accident occurred.

Jyunpei does not possess any special physical abilities beyond his cursed gift of understanding feline speech. His development throughout the series is modest; while he initially prioritizes his love life, he shows a growing, albeit reluctant, sense of responsibility in attempting to grant the cats' wishes to break his curse. The story leaves many of his personal and supernatural challenges unresolved.