Betrayed and killed by her organization, the top assassin Blood Shadow reincarnates in the abused high‑school girl Isabelle. Hiding her deadly combat, hacking and medical skills, she protects her disabled younger brother Ethan, fights campus bullies and greedy relatives. She earns huge wealth through street racing, crosses paths with powerful tycoon George Harris and the Blackwater Mercenary Group, and secretly plots revenge against the enemies who destroyed her former life.