Within less than half a year of marriage, their sex life had completely dried up, and due to work stress, there were days when he barely even saw his wife's face. Amid this situation, he began to notice something strange about the behavior of his younger brother-in-law, Jiro, who lived with his wife. There was something different—something that went beyond a simple brother-in-law and sister-in-law relationship. He had always been serious and responsible, often scolding his carefree younger brother who never held a steady job, envious of his free-spirited nature despite being of an age where stability was expected. Yet beneath these feelings lay a hidden jealousy toward his own wife.