During a business trip, I receive a sudden phone call from my wife, Arisa. Admitting to myself that I've been feeling lonely, I answer the call and learn that Arisa's sister's husband, Takefumi, has come over to their house. I'd met Takefumi once before at a drinking party—he's a cold man who sees women merely as sexual objects. I'd sensed from the beginning that he had his eyes on Arisa, but I never thought he'd show up while I was away. The situation is rapidly growing more complicated.