The story revolves around the Tachibana family, who live in a 2.5-generation household. In this type of household, the parents and their children live together in a two-generation home, with the addition of a single sibling from the younger generation. The Tachibana family decides to rebuild their old home into a 2.5-generation household, and the 40-year-old unemployed and reclusive protagonist, Masaharu Tachibana, ends up living with his sister and her family.

Although Masaharu is revered as a gaming expert in the virtual world, he faces challenges in his new living situation as his sister asks him to help with household chores, and his teenage niece rejects him as "weird." Having lived life at his own pace until now, Masaharu gradually learned to interact with people and regain a more social lifestyle amidst the changing environment.