Mona-chan is a sister who has a complicated siscon and is dating her older sister's ex-boyfriend, and Koko-chan can't help but find her cute sister adorable. When they get drunk, the sisters' long-awaited orgy breaks out!? They have raw sex with their ex-boyfriend and current boyfriend, and they cum nonstop! They have zero ethics, and they take turns having forbidden sex! They're so siscon that they even share their boyfriend, and it's a drunken orgy party with beautiful sisters! These sisters are too dangerous!