After a devastating attack on Guren's ­high school, war has officially broken out between his family's mortal enemies, the Order of the Imperial Demons, and their rival syndicate, the Brotherhood of a ­Thousand Nights. Amidst the chaos, Guren's childhood love Mahiru Hiragi leaves him with a chilling prophecy: this year, at Christmas, the world will come to an end. In his struggle to decipher the riddle and piece together a path to survival, Guren is forced to relinquish his last illusions of freedom and serve the Imperial Demons' presumptive heir. But when Guren's first orders dispatch him and his friends on a mission straight into the jaws of all-but certain death, he must decide whether to abandon his ambitions and live to see another day or make a deal with the devil destined to send him down a one-way road to hell.