Issei Hyoudou is a typical high school student who spends his days being a pervert, with no real ambitions other than building his own harem. His life takes an unexpected turn when he is asked out on a date by a stunning girl, who turns out to be a fallen angel that tragically kills him. Fortunately, Issei is given a second chance at life when the gorgeous senior student Rias Gremory, a top-class devil, brings him back to life as her servant and invites him to join the prestigious Occult Research club at school. As Issei adapts to his new way of life, he must train and fight to survive in a world ruled by angels and devils. Along the way, he encounters many hilarious (and sometimes scandalous) moments with his new friends, all while keeping his new existence a secret from his loved ones in High School DxD!