Sakura Sakurakouji, a cheerful and skilled martial artist, witnesses a gruesome incident where people are engulfed in blue flames on a bus, prompting her to report it to the police. However, all evidence of the crime vanishes, leaving her doubting what she saw. The arrival of Rei Oogami, a new transfer student, reignites her suspicions as he seems to be the boy she previously accused of murder. Unbeknownst to Sakura, Rei has the power of a Code Breaker, aiming to mete out justice according to his own "eye for an eye" principle.