When unlucky high school letch Issei is murdered by his first—ever girlfriend on his first—ever date, who should jump to his rescue but the hottest girl in school, Rias—senpai! She informs Issei that he's been reincarnated as a demon and that it's about time he got to work—for her! Caught in the bosom of an age—old war between angels and demons, Issei soon discovers that being enslaved by a demonic beauty isn't quite all that it's cracked up to be!