In a dark, oppressive, and industrially decaying Tokyo, meek salaryman Taniguro leads a quiet life with his partner, Chisato, and their young son. This fragile domestic tranquility shatters when a violent gang of skinhead cyber-punks brutally abducts and murders the child. Consumed by grief and a raging thirst for vengeance, Taniguro is plunged into a surreal nightmare when he confronts the gang's sadistic leader, a charismatic fanatic known simply as the Guy.Instead of finding mere death, Taniguro discovers a terrifying biological truth about himself. The extreme
psychological trauma of his son's murder acts as a catalyst, unlocking dormant, horrific mutations within his own flesh. His body begins to aggressively morph, mutating organic tissue and cold industrial iron into massive, grotesque weaponry. The Guy recognizes Taniguro as a kindred spirit, a fellow human weapon forged by dark scientific experimentation from their shared past. The gang's ultimate motivation is not merely criminal; they are part of a radical cult seeking to purge weak human emotion through forced cybernetic evolution, and they want Taniguro to be the centerpiece of their new metallic army.Rather than submitting to the cult, Taniguro's protective instincts and boiling rage override his humanity. As the
transformation accelerates, his right arm swells into a terrifying, heavy-caliber pneumatic drill-hammer. The Guy kidnaps Chisato to force Taniguro's complete surrender and final integration into the metal hivemind. Driven by a desperate need to save the woman he loves and avenge his son, Taniguro fully embraces the body horror gripping his form.He storms the cult's subterranean lair in a relentless rampage of industrial carnage. The confrontation culminates in a monumental, apocalyptic showdown between the two hyper-evolved metal men. Their flesh and steel grind together in an explosive display of sparks, blood, and biomechanical fury. Taniguro defeats the Guy by weaponizing his overwhelming paternal grief, shattering the tyrant’s metallic shell. With the cult destroyed and Chisato rescued, Taniguro realizes his transformation is irreversible. He stands isolated as a towering monster of jagged steel and pulsing flesh. Rather than retreating into society, he steps out into the neon-drenched Tokyo streets, his body radiating an unstoppable, destructive energy. He is no longer just a victim; he is the ultimate engine of flesh and iron vengeance, ready to reshape the corrupted world around him in his own terrifying image.