Yōhei Mochizuki, upon ego-searching his name before entering the prestigious Aleyster Academy, discovers a strategy guide revealing his fate as a minor character defeated early on by the protagonist in a game-like world. Refusing to accept this, he uses his unique ability as a 'Gaist' user (one of ten thousand) to defy his predetermined role. With the help of his spirit partner, 'Gobimi,' whom he evolves into a beautiful girl, he aims to surpass the game's protagonist and all those who underestimated him. This is a story of a man fighting against his destiny as a weak mob character and his spirit partner striving for strength together.