Clary, following the Lightwood family and Jace, ends up in Alicante, the capital of Idris, where the last weapon, the Mirror of Death, is kept, which Valentine is hunting for. Only the one in whose hands this Mirror ends up will survive and find peace. In the fight against Valentine, the Nephilim will unite with werewolves and other undead, and Clary will receive a new rune from the hands of the angel Ithuriel, but the girl will find out what it means only after the decisive battle. All the secrets and all the riddles will be solved, but most importantly, what future awaits Jace and Clary? - the one who turns the last page of the trilogy will find out.