Emma is torn between her passion for Julian and her need to protect him from the consequences of a forbidden romantic partnership, a situation challenged by her relationship with Mark and his efforts to regain his Shadowhunter capabilities.

As Fjerda's massive army prepares to invade, Nikolai Lantsov will summon every bit of his ingenuity and charm to win this fight, and Zoya Nazyalensky must embrace her powers to become the weapon her country needs, meanwhile Nina Zenik risks discovery and death as she wages war on Fjerda from inside its capital.