After her divorce, she raised her son alone, but he got a job this spring and moved to Tokyo. She was worried that he would just go away... When she felt lonely, her son invited her on a graduation trip just for the two of them, to show his gratitude. A trip just for the two of them, a hot spring bath together... Even though they are father and son, they are still man and woman. Her feelings of love turned to desire, and her suppressed sexual desire overflowed, and she took her son's penis into her mouth. A forbidden mother-son incest story in which they reveal their instincts and make love over and over again.