Yuji Sakai is an ordinary high schooler until a Flame Haze named Shana reveals he has already died, sustained now only by a Treasure Tool called the Reiji Maigo, the Midnight Lost Child. Drawn into the war between Flame Hazes and the Crimson Denizens who feed on human existence, Yuji joins Shana's fight in Misaki City while trying to hold on to an ordinary life. Their bond deepens as they face down Denizens hunting for the Reiji Maigo's power.