خلاصه داستان : دو برادر با اختلاف سنی زیاد به نام‌های ریوچی کاشیما و برادر کوچکتر او کوتارو پس از مرگ ناگهانی پدر و مادرشان در سقوط هواپیما یتیم شده‌اند و خانه‌ای ندارند. رئیس آکادمی معتبر Morinomiya که خود پسر و عروسش را در همان سانحه ی هوایی از دست داده است، پیشنهاد می‌کند که پسران را تحت مراقبت خود قرار دهد و به آن‌ها خانه جدید و امکان تحصیل رایگان بدهد.

After losing both parents in a fatal plane crash, teenager Ryuuichi Kashima must adjust to his new life as the guardian of his younger brother Kotarou. Although Ryuuichi is able to maintain a friendly and kindhearted demeanor, Kotarou is a reserved toddler still too young to understand the reality of the situation. At their parents' funeral, they are approached by Youko Morinomiya, the stern chairman of an elite academy, who decides to take them under her care. However, there is one condition Ryuuichi must fulfill in exchange for a roof over their heads and enrolment in the school—he must become the school's babysitter. In an effort to support the female teachers at the academy, a babysitter's club was established to look after their infant children; unfortunately, the club is severely short-staffed, so now not only is Ryuuichi responsible for his little brother, but also a handful of toddlers who possess dynamic personalities.