The Dagger and the Flame - Doyle, Catherine

In Fantome, a city of cobbled streets and shadowed catacombs, thieves and assassins wage war for control of Shade-magic—a scarce and lethal power. Seventeen-year-old Seraphine, orphaned on the night her mother was murdered, finds refuge with the Cloaks and vows vengeance on their enemies, the Daggers. But when she crosses paths with Ransom, heir to the Daggers and as deadly as he is magnetic, Sera discovers her own strange magic may be the key to unraveling the guilds’ bloody feud. Torn between vengeance and desire, forgiveness and betrayal, Sera and Ransom must decide whether their bond will ignite a future—or burn them both to ash.