High Warlock Magnus Bane learns that a demon-worshipping cult, the Crimson Hand, is wreaking havoc across Europe, threatening more than just his romantic getaway with new boyfriend, Alec Lightwood. High Warlock Magnus Bane and his new lover, the mortal Alec Lightwood, are celebrating their survival and victory in the Mortal War by touring the world. But the world won't leave them alone-- Magnus learns that a demon-worshipping cult, the Crimson Hand, is wreaking havoc across Europe. When he takes possession of a powerful spell book of dark magic known as The Book of the White, there are many who want to claim it for themselves. -- adapted from jacket

"A Shadowhunters novel" -- Cover.