Phil, a former hero who defeated the Demon Queen fifteen years ago, is now a forty-something-year-old adventurer who remains a virgin. The reason is his very specific fetish: he is only aroused by monster girls. Unable to reveal this desire to anyone, he devises a plan to make it appear as though he is engaging in battle with monster girls, only to be willingly defeated by them, as he believes this will lead to them having their way with him. His targets include succubi, slimes, and alraune. The story follows Phil as he attempts to turn this lifelong fantasy into reality.

The main character is Phil, a powerful but socially awkward former hero whose heroics have left him unfulfilled due to his hidden desires. The setting is a fantasy world where monsters and humans coexist, though monster girls are typically seen as enemies to be fought rather than partners to be desired.

The narrative begins with Phil establishing his daily routine of seeking out monster encounters. As he stages these mock battles, he encounters various monster girl types, each presenting unique challenges and opportunities for his goal. A notable narrative thread involves Phil's attempts to balance his public image as a capable adventurer with his private quest for monster girl defeat. The story follows a pattern of Phil seeking out specific monster species, attempting to lose to them, and navigating the often-comedic or unexpected outcomes of these encounters. His ongoing struggle remains whether he can successfully achieve his dream of being overpowered by a monster girl and having a sexual encounter with one.