Yumi, whose husband passed away several years ago, lives with her son. One day, she peeks at her son having sex and gets excited, groping her crotch. Then, in the middle of it, her eyes meet with her son's. Unable to control herself, Yumi makes love to her son, even though she knows it's wrong. The son also regrets having had a relationship with his mother, but becomes addicted to his mother's body.