Matsuko Kogure lives with her husband Yuuji and their children, Kousuke and Yuko, in a modest older house purchased from Yuuji's close friend Matsurida, fulfilling a long-held family aspiration. This stability is disrupted when Matsurida asks them to temporarily care for Gorgeous, the dog belonging to his mistress Kanna. Matsuko resents the imposition, criticizing Yuuji's inability to refuse Matsurida and comparing his compliance to a dog's behavior. Gorgeous instinctively defers to Matsuko as the household authority.

The situation escalates as Kanna, unwilling to leave her dog, moves into the Kogure home uninvited. Kanna's presence deeply frustrates Matsuko. She wins over the initially disapproving children: offering Kousuke his favorite Tsukiyaki and a video game console, and bonding with Yuko through swapping clothes and taking photos. Yuuji also warms to Kanna. Matsuko alone remains resistant, disappointed by Yuuji's passivity.

A pivotal confrontation erupts when Matsurida's wife arrives, having discovered the affair and Kanna's location. Amid the argument between Matsurida, his wife, and Kanna, Yuuji reveals he fabricated Matsurida's affair to hide his own infidelity with Kanna. He orchestrated the arrangement, including Matsurida taking false responsibility, to avoid Matsuko's suspicion. Matsuko is profoundly shocked. Yuuji presents a photo of himself with Kanna as proof, later exposed as staged using an image from Kanna's clothing exchange with Yuko. Post-revelation, Yuuji adopts a newly confident demeanor, and Gorgeous transfers loyalty from Kanna to him.

Beyond this narrative, Matsuko and Gorgeous appear together purchasing pork near a bento shop featuring a man in a rabbit costume. She also features in a brief cameo with Gorgeous within the "Middle-Aged Teen" storyline.