Gibomai ~Haitoku no Kyouen~

A celebrated painter succumbs to heart disease, leaving behind his much younger wife Megumi and her daughter Yuna. His son Kyosuke, who never approved of the union, schemes to evict them. Megumi proposes a desperate deal: if Kyosuke lets them stay, he can do anything he wishes with Yuna, his step-sister. Kyosuke accepts, setting the stage for a dark tale of forbidden desire and twisted family bonds.