Innocent blood has been spilled on the steps of the Council Hall, the sacred stronghold of the Shadowhunters. In the wake of the tragic death of Livia Blackthorn, the Clave teeters on the brink of civil war. One fragment of the Blackthorn family flees to Los Angeles, seeking to discover the source of the disease that is destroying the race of warlocks. Meanwhile, Julian and Emma take desperate measures to put their forbidden love aside and undertake...