Dreaming of becoming a hero and vanquishing the Demon King, Raul Chaser enters the Hero Training Program in pursuit of his ambition. However, when the Demon King is defeated and peace returns to the world, the Hero Training Program is suspended indefinitely, making it impossible for anyone to become a hero.
Two years later, Raul reluctantly works at a small electronics store called Magic Shop Leon. Though the former hero-in-training is plagued by the mundanity of working in retail, everything changes with the arrival of a new hire. Appearing at first to be just a boy with good looks, "he" turns out to be a female demon by the name of Fino Bloodstone. She is not just any old demon either—Raul's new coworker is in fact the daughter of the late Demon King! Handed the responsibility of training this eccentric new employee, Raul soon finds his life becoming livelier than it ever was before.
Summary taken from: MyAnimeList