The Infernal Devices, book 1: Clockwork angel

Tessa Gray thought her journey to London would be the beginning of a new life, but she never could have envisioned the dark turn that life would take… Abducted upon her arrival, Tessa is introduced to London’s Downworld, the sordid supernatural underbelly of the city, and informed that her future will be recast to service a man known as “the Magister.” Only the intervention of the London Institute’s Shadowhunters delivers the girl from this fate, but sinister forces are still gathering around Tessa. Even so, Tessa’s attraction to two of the young Shadowhunters who have taken her under their wings may prove more dangerous by far…