Hyakunichikan!!

Synopsis

High school student Shuto is looking forward to being free and at ease while his parents are working overseas. Only problem is, things don't exactly go as planned when he finds a 5 year old girl in his house. As it turns out, the girl's mother is a colleague of his parents and is traveling overseas with them and has left her daughter in his care for the next 3 months!! (Source: MU)