Keiko, a married woman whose husband is often away on business, spends a lot of time alone with her son. One day, her son's friend, who came to stay overnight to write a report, witnesses Keiko masturbating. When the two are alone, he pretends to be sick and rapes Keiko. Even though he was raped, her body responds to a long-forgotten pleasure, and she becomes intoxicated with the orgasm that comes. Her friend's desires run wild, and she is caressed by her son next to him, and before long she becomes immersed in an affair with them...