Musuko no Tame nara Midara ni Nareru Haha

Yayoi discovers that her neighbor Hikami Sae loves to have sex with younger men. Her next target is Yayoi's son Yuuta. To save her son from being corrupted by Sae she allows herself to be blackmailed by her. Sae brings Yayoi into her own dark world, a world of the pleasures of the flesh. Again and again Yayoi has sex with an unknown young man all for the sake of her son. Slowly she sinks into a forbidden world before she discovers too late that the boy she's having an affair with is her own son Yuuta.