Haha Sange 義母散華～ははさんげ～

Tomonori is a university student. His mother passed away two years ago, but his father, Seiichi, soon got remarried to Hanae. He now happily lives with Seiichi, Hanae, and Marie, Hanae's daughter. But one day, he gets to know the fact that Seiichi had been committing adultery with Hanae. "He betrayed my mother.... Ok, I'll destroy everything around him! I'll steal his wife first." His devotion to Hanae has got crooked and his revenge starts though he knows it'll put his family into misery and he'll never be able to turn back....