Darkness returns to the world of the Shadowhunters. Their society falls apart again, and then Clary, Jace, Simon and their friends must come together again for the greatest battle against a terrible evil enemy - Clary's own brother. Sebastian Morgenstern forces the Nephilim to go against their brothers. Using the Mortal Cup, he separates families and lovers and turns Shadowhunters into creatures of darkness to join the ranks of his dark army. Love will be sacrificed and many will give their lives in a terrible battle for the fate of this world in the gripping final novel of the Mortal Instruments series. .