In Misaki City, the inhabitants of the Crimson Realm pose a constant threat as they drain the life energy of its people. The protection of humans falls to the Flame Hazes, among whom is Shana, also known as the "Flame-Haired Burning-Eyed Hunter." She takes a keen interest in Yuuji Sakai, an unwitting teenager who has been caught up in the fight between the Crimson Denizens and Flame Hazes. Yuuji and Shana's relationship soon develops into more than just friendship, but understanding her hot-and-cold personality proves a challenge for him. Their peaceful existence is disrupted with the arrival of a transfer student who bears a striking resemblance to a previous enemy. As they brace themselves for another attack by their Bal Masqué adversaries, Yuuji and Shana must join forces to unravel the secrets surrounding the "Midnight Lost Child," a mystical object within Yuuji's body that everyone is after.