In the absence of their deceased mother and debt-ridden father, sisters Kyou and Asu Yamada are compelled to look after themselves. Fortunately, they do have shelter: a small room in an old apartment large enough to accommodate both of them. Yet, to make ends meet, the older sister Kyou works hard to balance various part-time jobs—all while ensuring that she and her younger sister can continue their studies. Despite these difficulties, they are not alone. Surrounded by seemingly good and kind people, Kyou and Asu's lives are far from miserable. Above all, the two sisters share a precious bond that, regardless of any pain, trials, or quarrels that may arise, will always remain unbreakable.