Mio has a one-night stand with a former classmate at a class reunion, and is filled with guilt towards her husband and worries about getting pregnant. Her brother-in-law, Takashi, who happened to be in Tokyo and staying the night, noticed that Mio was acting strange and began to investigate. ``According to what I heard from my brother, we don't spend much time together at night, but my sister-in-law seems to be worried about her getting pregnant. Maybe she's cheating on me...'' Takashi, who had had his eyes on Mio since they first met, uses this as a bait to approach Mio...