As a Code Breaker, a super-powered assassin for a secretive government organization, when Rei Ogami gets an assignment he has no problem killing criminals by cremating them with his blue fire blaze. When Sakura, a classmate of Rei's, witnesses his fatal flames in action, she makes it her mission to keep him from killing again. But she must keep his power a secret to protect her parents, classmates, and best female friend Aoba, who mistakenly thinks Sakura and Rei have mutual feelings. But Rei is interested in Sakura, who's immune to his fire, as she may be a "Rare Kind."