Until the dreams began, she was just Emma Ricci, the adopted Korean child of American parents and recent graduate of the Fashion Institute of Technology. She didn't even know demons existed until she met Li Bai and Zhan Ziquian, who told her she's destined to be a hellgate closer. Now she's M, a member of an ancient order of warriors-and her missions are more dangerous by the day.
M travels to China to return a hellgate key to its repository in the Yellow Mountains. In China, she learns the secret origins of her warrior line and searches for her long lost twin sister.
Meanwhile, in Paris, a crazed university professor summons a ghost-like succubus to the Sorbonne campus. M arrives with Zhan, Li Bai, and her loyal hellhound, Blue, to drive the succubus back to where she belongs and rid the Paris catacombs of its demon infestation. The struggle takes M and Blue straight to hell, revealing unexpected allies and horrible new enemies. If they're lucky, M's powers will bring them back. As M learns in China, however, even hellgate closers can't always stem the demon tides. Most die trying, and this fight might spell the end of M.