Mario Kuga agrees to help his father revive a failing VR RPG called Fantastic Kingdom VR in exchange for Game Master privileges. Using his power to modify the game's data, Mario targets his shy classmate, Koharu Takashina, promising her a world where she can be a confident protagonist. Instead, he traps her in a perverse simulation as a prostitute, using his administrative powers to subject her to sexual pleasure and ensure she cannot log out of the digital world.
Mario sets his sights on Natsume Saya, a strong and popular classmate, tricking her into entering the virtual world of FKVR as a "Heroine." Using his GM authority, Mario rigs the game to strip Natsume of her power and subject her to an overwhelming sexual encounter with a tentacle monster. Though initially horrified by the experience, the intense pleasure leaves Natsume addicted, prompting her to beg Mario for another chance to play.