Yuta returns to his wife's parents' home after a long time. He is always captivated by the unchanging beauty of his mother-in-law, Yuka, despite the passage of time. That night, his wife leaves for a class reunion, leaving Yuta and Yuka alone for dinner. To help Yuta relax, Yuka offers him alcohol, but she ends up getting drunk herself and, unable to suppress her rising desires, pushes Yuta down and has sex with him. The next day, Yuka regrets what happened under the influence of alcohol and tries to act as if nothing happened, but once she remembers the pleasure, she can't forget it...
