Clary follows the Lightwood family and Jace to Alicante, the capital of Idris, where the last weapon, the Mirror of Death, is kept, which Valentine is hunting. Only the one in whose hands is the Mirror will stand out and find peace. In the fight against Valentine, the Nephilim will unite with werewolves and other undead, and Clary from the hands of the angel Ituriel will receive a new rune, but what does it mean that the girl learns only after the decisive battle? All the mysteries and all the mysteries will be solved, but most importantly - what is the future for Jace and Clary? - will find out who will turn the last page of the trilogy