The protagonist, Kousaka Yuusuke, is an ordinary college student who loves eroge. One day, Yuusuke has a dream where he overpowers someone. In front of such a Yuusuke, two girls who call themselves goddesses, the eldest daughter, Yorus and the second daughter, Fauna, appear and suddenly attack him, saying, 'Excuse us, but please die for the sake of world peace!' It turns out that the Demon King is asleep inside Yuusuke, and seeing obscene dreams causes 'impurity' to accumulate, which will awaken the Demon King.
