Tooru was enjoying a brief taste of freedom. His wife had returned to her parents' home to prepare for childbirth, leaving him alone in the house. He wasn't thinking about taking advantage of the situation for some womanizing—he simply didn't have that kind of mindset. Instead, he passed his days quietly, watching TV and reading books. But that night, his sister-in-law Sayu suddenly showed up. Claiming she had come to take care of him in his wife's absence, her true intentions were focused on her brother-in-law's body. With a seductive smile, she set her sights on Tooru's heart. As the night closed in around them, the atmosphere slowly turned dark and dangerously charged.