Yusaku Koga, a 51-year-old middle manager at an outsourced call center, reluctantly visits the Nakagyō Kokoro Clinic for the Soul. After climbing five flights of stairs, he is ushered past the waiting room by a curt Chitose and meets a young doctor. Initially told the clinic is not accepting new patients, Koga insists on treatment, and the doctor makes an exception.

Koga explains his problem: He is experiencing insomnia, which he ties to his new boss, Hinako Nakajima, a cheerful deputy general manager who constantly repeats the phrase, “I like it!” (103). Her voice haunts his dreams. He had expected to succeed the retiring general manager, but Hinako was suddenly promoted above him. The doctor decides to prescribe Koga a cat for 10 days, calling it a highly effective treatment for insomnia. Chitose brings in Margot, a mixed-breed tortoiseshell female, and Koga leaves the clinic with the cat, a carrier, and supplies, covered in fur.

At home, Koga’s wife, Natsue, reminds him she is allergic to cats, which he had forgotten. She reluctantly agrees to let him keep Margot for 10 days if she stays in the spare room. Their college-age daughter, Emiri, is away on a trip. Koga reads the instruction leaflet and learns to feed and care for Margot, a three-year-old mixed-breed cat.

That night, Koga sleeps in the spare room with Margot, but she meows incessantly at the window, preventing him from sleeping. The next morning, Koga is exhausted and nauseated. At work, Hinako cheerfully greets everyone with compliments. General Manager Fukuda complains about Hinako’s high energy, but Koga has a moment of empathy, realizing Hinako is adjusting to a new environment and he has been unsupportive. At lunch, Koga awkwardly tries to compliment two young female coworkers, but realizes that he has said it while they are viewing lingerie and retreats in embarrassment.

When Koga returns home, Emiri has returned, and she and Natsue are happily playing with Margot. Natsue has obtained medication for her mild allergy and moved Margot’s supplies to the living room. Emiri smiles at Koga, a sight he has not seen in years. Jealous of being left out, Koga insists that Margot is his cat and that she will sleep with him. For a second night, Margot meows constantly and Koga gets no sleep.

The next morning, Koga is so exhausted he falls asleep on the commute train and wakes at the final stop in another prefecture, hours late for work. He calls in with a false health excuse, then angrily returns to the clinic. He confronts the doctor, complaining the cat kept him awake for two nights. The doctor observes Koga’s disheveled appearance, drool traces, and a well-rested look, indicating he slept deeply on the train. Koga realizes he had a pleasant dream and that Margot’s meowing prevented his usual nightmares about Hinako. When the doctor offers to prescribe a different cat, Koga panics and insists on keeping Margot for the full 10 days. The doctor gives him a new prescription. Chitose provides Margot’s worn-out cushion bed and instructs Koga to leave doors open so Margot can roam freely.

Following the new instructions, the family leaves doors ajar, and Margot sleeps in various places, including on Koga’s chest, forcing him to lie rigidly. The family begins gathering where Margot is, a departure from their usual routine. While talking about the value of getting likes on social media for her pictures of Margot, Emiri explains that giving compliments requires energy and is more complex than Koga thinks it is. She then suggests he use pictures of Margot to connect with colleagues. She theorizes that Margot’s name may come from five circular white patches: combining the words for “circle” (maru) and “five” (go) to form “Maru-go.”

Koga’s insomnia and nightmares disappear. At lunch one day, he finds Hinako alone in a secluded hallway, looking weary. He shows her a video of Margot sleeping on her back with paws crossed, resembling Tutankhamun’s sarcophagus. Hinako laughs and says she likes it. Koga sincerely tells her that her compliments bring people joy, which makes her smile shyly. He realizes that giving praise requires effort, especially when managing a large team, and that Hinako’s enthusiasm is valuable.

After Margot is returned to the clinic, the family feels her absence. Natsue suggests adopting a cat. They visit a mall pet store filled with expensive purebred kittens, but Koga feels uneasy about the selection process. Emiri proposes visiting the City Cat Rescue Center instead, arguing the pet store cats will easily find homes, while shelter cats need more help.

At the shelter, they meet deputy director Tomoya Kajiwara, who looks strikingly like the Nakagyō Kokoro Clinic doctor. Koga suspects they are the same person, but Kajiwara denies working at the clinic, saying he only knows of Dr. Kokoro Suda’s Suda Animal Hospital in the area Koga describes to him. The family is drawn to a three-year-old calico with asymmetrical facial markings that Kajiwara says is unpopular. Koga impulsively names her Six-Patch, combining her cage number (six) with the fact she has many patches. The name sticks despite Emiri’s initial protest. They decide to take Six-Patch home for a trial stay.

After Emiri posts about the adoption online, the name “Six-Patch” receives many likes from her followers. Though Koga claims to be above empty praise, he is secretly pleased and looks forward to sharing photos of their new cat, having learned the value of connection through praise.