One month after my father remarried a beautiful and kind woman named Tsubaki, we brothers were falling in love. Before being a mother, I am conscious of being a woman. However, she felt frustrated with Tsubaki-san, who only loved her brother who was good at both her studies and sports. The relationship between my brother and Tsubaki-san was heating up while stealing my father's eyes, and before I knew it, I was in a relationship of taking a bath together. One night, Mr. Tsubaki sneaks up to the bunk bed where we brothers are sleeping...
