Red fog sweeps across the city, and sinister creatures emerge. During her escape, an ordinary young woman named Wanzhou loses her left arm but unexpectedly awakens the abilities of a mechanic. She can dismantle components and modify vehicles, yet her companions continue to look down on her, and she even suffers betrayal and abandonment. From modifying electric scooters to building a mechanical arm and steel wings, she grows stronger through one perilous encounter after another and gradually learns to trust new companions. When sinister creatures surround the convoy, the girl who once could only struggle to keep up finally steps forward, using machinery and courage to forge a way to survival for everyone.