After the death of her parents, Kanami Tachibana's once kind older brother suddenly changes for the worse, leaving her to fend for herself. When Makoto Asahi finds her like this, he offers up to become a brother to her. Kanami, feeling the kindness she once felt with her brother and scared to forget her sibling, offers to pay him money for this deed. As their bond strenghtens and Kanami gets to see more of the world than ever, will she get back the kind brother she once loved?