A powerful dungeon lies in the depths of the earth, filled with lavish treasures. Enticed by the promise of wealth, many adventurers traverse the dangerous underground maze, only to be halted at the very last chamber where Callistra, the Final Boss, lies in wait. She is a powerful magic wielder and no one has yet to best her in battle. Many adventuring parties have given up trying to challenge Callistra at all, leaving the dungeons before reaching the Final Boss.
In turn, Callistra has become terribly bored of her position and wishes to be free from it. Her monotonous life is finally broken up by Ruth, a brave knight that refuses to give up in defeating the Final Boss and defeating the dungeon once and for all. Both are evenly matched and should be wary of the other, but instead other emotions arise instead...