Uchi no Otouto domo ga Sumimasen follows Ito, a first-year high school student whose life changes during spring break when her mother remarries and the family is forced to move. Suddenly, Ito finds herself living under the same roof as four younger stepbrothers, and the home she enters is full of unfamiliar routines, awkward silences, and the daily challenge of becoming part of a brand-new family.
Ito is determined to get along with everyone and make the arrangement work, even when the atmosphere feels tense. The most difficult person to understand is Gen, the eldest brother, whose distant manner makes him hard to read. As Ito spends more time with her new siblings, however, she begins to notice quiet signs of warmth and kindness behind his cool exterior.
Balancing domestic comedy with gentle emotional beats, Uchi no Otouto domo ga Sumimasen centers on the friction, trust, and gradual closeness that can grow inside a blended family as Ito learns how to fit into a house that is no longer entirely her own.
