Two years ago, Chiaki's husband became impotent, leaving her trapped in a sexless marriage and tormented by daily loneliness. One day, she accidentally walks in on her son Keita masturbating in his room. Unable to resist, she begins to seduce him. "Masturbation can't possibly satisfy you, can it? Why don't you have sex with your mother?" Drawn to his youthful, throbbing cock, Chiaki gives in to her uncontrollable desires and tempts Keita. But Keita is no ordinary boy—he's a stamina monster who won't let things end quickly. As their lust ignites, the forbidden mother and son indulge in relentless sex until dawn, again and again, lost in an endless spiral of pleasure.