Nakadashi Haramase Oyako Donburi

Hiroki has lived alone with his sister Ruka for many years. One day there's a knock on the door and a tiny little girl stands in the doorway. Ruka instantly recognizes the small lady as her mother Mikan who has lived in Yemen since Hiroki was born. She has returned home and wishes to live as family again but can Hiroki overcome the feeling of abandonment he had as a child? Can they simply start living as a family again after so many lost years? Or will something build in them that goes against the feeling of 'family'?