Ciudad del Fuego celestial

Darkness has descended upon the Shadowhunter world. Clary Fray's own brother, Sebastian Morgenstern, is moving against the Nephilim, systematically turning Shadowhunter against Shadowhunter. Using the Infernal Cup, he transforms them into monstrous creatures, tearing families apart and swelling the ranks of his Endarkened army. The embattled Shadowhunters have withdrawn to their ancestral home of Idris, but not even the famed demon towers of Alicante can keep Sebastian at bay. As chaos and destruction overwhelm them, the Clave is pushed to the brink of annihilation.

With the world of the Nephilim falling apart, Clary, Jace, Simon, and their friends must band together to fight the greatest evil they have ever faced. But Sebastian seems unstoppable. His power grows with every victory, and no weapon in this world seems capable of defeating him. With their options exhausted, the small group of heroes must contemplate a perilous journey into the demon realms, a place where no Shadowhunter has ever set foot and from which no one has ever returned. This final, desperate gambit will demand a terrible price, forcing them to risk everything as they face a battle where lives will be lost, love will be sacrificed, and the very fabric of their world will be changed forever.