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.

On the surface, Ryousuke Kaga is the token perverted teenager, spending his days ogling women and indulging in erotic reveries. Because of this, Ryousuke is ostracized by his classmates. Only his childhood friend Mina Okura knows that behind his lecherous persona lies a compassionate boy who has sworn to be chivalrous to girls, believing they are treasures that must be protected. One fateful day, Ryousuke runs into Lisara Restall, a Soul Reaper hailing from a noble family, whose primary objective in the human realm is to locate a magically potent person known as the One. In order to fuel her movement with magic, she decides to form a provisional contract with Ryousuke: to use his sexual desires as a source of energy. Carrying out this peculiar arrangement with Lisara, Ryousuke encounters many disparate individuals but also learns of the intriguing yet dark secrets surrounding his world.

With their school's pool opening the next day, Iria schemes up the idea to hold a swimsuit contest. With Lisara, Mina, Quele, and Iria herself all participating in the event.

Thirty years ago, the Eurasian continent was devastated by a supermassive spatial quake—a phenomenon involving space vibrations of unknown origin—resulting in the deaths of over 150 million people. Since then, these quakes have been plaguing the world intermittently, albeit on a lighter scale. Shidou Itsuka is a seemingly average high school student who lives with his younger sister, Kotori. When an imminent spatial quake threatens the safety of Tengu City, he rushes to save her, only to be caught in the resulting eruption. He discovers a mysterious girl at its source, who is revealed to be a Spirit, an otherworldly entity whose appearance triggers a spatial quake. Soon after, he becomes embroiled in a skirmish between the girl and the Anti-Spirit Team, a ruthless strike force with the goal of annihilating Spirits. However, there is a third party that believes in saving the spirits: Ratatoskr, which surprisingly is commanded by Shidou's little sister! Kotori forcibly recruits Shidou after the clash, presenting to him an alternative method of dealing with the danger posed by the Spirits—make them fall in love with him. Now, the fate of the world rests on his dating prowess, as he seeks out Spirits in order to charm them.