Ryosuke Kaga is an ecchi high school boy attending Momozomo Academy. One day, he meets a girl standing alone in the rain. She is Lisara Restor, an elite Grim Reaper, who visited the human world in order to find "The Singular Man". Ryosuke makes a contract with Lisara and she sucks energy required for her activity in the human world from Ryosuke. The source of the energy is his perverted spirit. To recover the sexual desire, Ryosuke has no choice but to help Lisara's search.