Junpei Takeda is thrust into another world alongside childhood friend Noriko Tatsumiya and persistent bully Kido Shouta—all summoned by divine intervention. While heroes manifest legendary strength, Junpei's stats prove inferior to even a common farmer's. Betrayed by the sole person he trusted and cast into a deadly labyrinth, he faces a dark journey of abandonment and fury. This underestimated summoned hero transforms weakness into ruthless power, ascending through cunning mastery and relentless determination—a path of revenge born from betrayal.