Magnus Bane and Alec Lightwood are settling into domestic life with their son Max when the warlocks Ragnor Fell and Shinyun Jung break into their loft and steal a powerful spell book....

All Magnus Bane wanted was a vacation—a lavish trip across Europe with Alec Lightwood, the Shadowhunter who against all odds is finally his boyfriend. But as soon as the pair settles in Paris, an old friend arrives with news about a demon-worshipping cult called the Crimson Hand that is bent on causing chaos around the world....