While his wife was away on a one-night, two-day trip with a friend, Akira was thoroughly enjoying his leisurely bachelor life. Suddenly, his sister-in-law, Yoriko, dropped by for a visit. However, unbeknownst to Akira, Yoriko, who had been having trouble with her husband recently, had planned to relieve her pent-up sexual desires with Akira. Unaware of this, Akira, having completely relaxed over a home-cooked meal, went to take a bath. Then, for some reason, Yoriko also came in...