Kimi Dake Shiranai Ch.9 Ver.0.9.0 by Kimi-Kun - Adult Sex Game

The protagonist lives a peaceful life alongside Yui, his devoted wife and a wedding dress designer. Everything changes when Yui receives a call from her mother: Kuroda, her drug-addicted brother, needs help again. Against their principles, the couple agrees to get involved once more, unaware of what might happen next.​