After losing her husband in a traffic accident, Chizuru raised her son, Tomohiro, alone. She began enjoying love again after meeting Akio, a widower, through a cleaning volunteer group. Though Tomohiro is drawn to his mother's pure feelings, one day he accidentally stumbles upon Akio forcing himself on her, watching in horror as his mother performs an intense blowjob. The shameful act takes place right in front of his late father's memorial portrait. Overcome with deep hatred and uncontrollable impulse, Tomohiro violently pins his mother down. Chizuru struggles desperately, but is overpowered by her son's strength and ultimately raped. Having crossed the forbidden boundary, what will become of this mother and son's twisted relationship?