Katsuragi Keima, a high school sophomore in class 2-B of Majima Academy, is a dating sim master and known as the "God of Conquest." Elsie, a demon descended from Hell, comes to speak to Keima for entering into a deal with the devil. In order to protect his life, he must capture the "Loose Souls" which exist in people's hearts. To do this, he must make real-life girls fall in love with him! A loose soul escapes into his classmate, track-and-field athlete Takahara Ayumi's heart. Will he really get her to fall in love with him?!