Kobo Tabata stands at the center of his narrative, living within a standard Japanese family in a typical domestic setting. His father, Koji Tabata, works as a regular office employee, while his mother, Sanae Yamakawa, maintains the household as a housewife. Kobo shares his home with younger sister Miho Tabata and maternal grandparents Iwao and Mine Yamakawa, who help manage family duties and care for the pets. The household includes a dog called Pochi and a cat named Mi. Kobo's uncle, the somewhat overweight high school educator Takeo Omori, is married to Sakiko Omori.

The family navigates ordinary yet occasionally unusual daily circumstances, often arising from Kobo's formative experiences or the household's routines and misunderstandings. Interactions between Kobo, his immediate family, extended relatives, and their pets form his core environment. Iwao Yamakawa is Kobo's maternal grandfather, while Takeo Omori is identified as Iwao's nephew—making Takeo Sanae's cousin and Koji's cousin-in-law. Consequently, Sakiko Omori is Iwao's niece-in-law and Sanae's cousin-in-law.