Filnansis

Mother warns main character to return home straight from school on his birthday day. Day passes just as usual, but he is delayed on the way home by the conversation with his childhood friend.
He find only wreckage on the place of his home with a note that makes no sense. Three girls suddenly appear and claim that protagonist is the successor of their country Grandfold where only girls live. He does not believe them until they take him to this country...