Mika has two secrets that she can never tell anyone... One is that she is having an affair with her son, Shintaro. Today, Shintaro clings to Mika again, and Mika accepts him because she is lonely without her husband. The other is that she has been developed by her son's friend, Shimada, and has become addicted to anal sex. One day, Shimada makes a suggestion to Mika, whose body cannot live without anal stimulation... Beautiful mature woman Mika Matsushita finally allows anal sex!!