As the story of the brothers unfolds, second son Yasuhiro Inoue and his mother Ayako Inoue temporarily stay at the home of her real sister and their aunt, Yukie Miyamae, due to renovations at their house. However, being away from their own home leaves the brothers feeling uneasy and perpetually unfulfilled. The mother, aware of being a guest, tirelessly devotes herself to housework, pouring her heart into chores as if it were her own home. Witnessing her like this, Yasuhiro gradually begins to notice something. And so does the eldest brother, Yohei Inoue, a busy elite salaryman who's always caught up in his demanding work life. Both become aware of it—the outline of their mother's bra showing through her clothes... From the small gaps in daily life, hidden emotions start to emerge.