Shoujikimono ga Baka wo Miru

Genchi is assigned the responsibility of caring for Maruu, a young girl who belongs to a group called the "Rooks." These children are destined to be sacrificed for their country upon reaching the age of sixteen. While many dismiss the "Rooks" as a mere urban legend, Genchi and Maruu know it to be real. Faced with the knowledge that their time together is limited, they must figure out what truly matters to them.