Don't Call it Mystery (Omnibus) Vol. 5-6 by Yumi Tamura
Kunou Totonou keeps finding himself right in the middle of mystery after mystery. After taking a tumble down a hill, Totonou is hurt and ends up in the hospital. There he meets a beautiful young woman named Leica. As he follows her coded instructions, he uncovers a disturbing urban legend about an Angel of Embers who's made it their mission to save children. But who exactly is this angel and what are their true intentions?