At 29 years old, Hiroto Ikuta works a part-time job at a fishing pond in the Tokyo neighborhood of Asagaya and has no real ambitions for a girlfriend, a full-time career, or a plan for the future. He spends his free time chatting with the locals, particularly his elderly neighbor Hanae Wada, a grumpy but kind retired school cook he affectionately calls Granny. When Hanae unexpectedly dies of a heart attack, Hiroto is surprised to discover she has left him her small house in her will, as she had no family of her own.

Three months later, Hiroto’s 18-year-old cousin Natsumi Kobayashi moves from her rural hometown to Tokyo to attend art school. With nowhere else to stay, she moves into the inherited house with Hiroto, whom she has not seen in years. The series follows this mismatched pair as they navigate life under the same roof, struggling with their seemingly mundane but emotionally rich daily existences. Hiroto is a former aspiring actor who abandoned his dreams after repeatedly failing auditions, while Natsumi is a sensitive and ambitious aspiring manga artist who finds the social pressures of the big city overwhelming.

The narrative unfolds through small, intimate moments rather than dramatic events, focusing on meals shared together, walks through the neighborhood, and the quiet weight of inheriting not just a house but the memory of the person who lived there. As the cousins adjust to their new living situation, their opposing personalities create a gentle but persistent tension. Hiroto's carefree, laissez-faire attitude towards life stands in stark contrast to Natsumi's anxiety and her tendency to assume the worst will happen. Despite these differences, they gradually build a strong connection, with Hiroto silently stepping up to support Natsumi as she makes mistakes and learns to adapt to art school, while her presence shakes him out of his emotional stasis following Hanae's death.

The series also develops a rich supporting cast of locals and friends. Hideki Noguchi is Hiroto's best friend from high school, now a married furniture store employee struggling to balance the pressures of work and fatherhood with his desire for simpler times. Yomogi Tachibana is a real estate agent whose efficient, career-driven values clash with Hiroto's relaxed pace, though fate seems to constantly throw them together. Natsumi finds her first friend in Akari Yokoyama, a kind classmate who helps her get a part-time job at a Chinese restaurant and encourages her manga ambitions. These interconnected lives form a quiet community in Asagaya, where each person is simply doing their best to figure out life, and where Hiroto's unassuming presence becomes an unexpected source of comfort for those around him.