Haruichi lost his parents and is left alone in the world. To uncover the truth of his parents' death, he makes a promise with his father's old friend to move into the Yaotome home and take care of their young daughter, Tsubaki. As he tends to the second daughter of the household who is being treated cruelly by her family, a peculiar picture lands in his hands. It shows the family head of the Yaotome family and a woman who mysteriously shares the same face as Tsubaki. Although the rumors say that Tsubaki's mother was just a concubine, this picture would prove otherwise. With doubts in his heart, Haruichi begins his investigation into the truth of Tsubaki's birth.