High school loner Haruka has been busy since he and his entire class were summoned to a fantasy world. Having driven out the insurrection-causing prince, now Haruka must face the Frontier Reclamation Army—tens of thousands of soldiers—to protect the frontier. Alone. And that army isn't the Theocracy's only weapon. They're causing artificial dungeon monster breakouts to terrorize the lands, plus the final ace up their sleeve... Something powerful enough to give the former dungeon boss, Angelica, a run for her money!