euphoria ~Manaka Nemu: the game from hell begins~

The protagonist Takatou Keisuke finds himself trapped in a mystrious sealed white room. With him is childhood friend Hokari Kanae, class chairman Andou Miyako, junior Makiba Rika, English teacher Aoi Natsuki, and his fellow classmates Byakuya Rinne and Manaka Nemu. A mysterious voice breaks over the speaker declaring, "The game is about to start." In order for them to escape they must play this game where the Takutou Keisuke is the “key”, the six ladies are the “keyhole” and that they have to perform specified unreasonable, radical, and immoral sex acts to “unlock” their freedom.