The Falconer (The Falconer Trilogy, book 1)
From the publisher:
Edinburgh, 1844. Beautiful Aileana Kameron only looks the part of an aristocratic young lady. In fact, she’s spent the year since her mother died developing her ability to sense the presence of Sithichean, a faery race bent on slaughtering humans. She has a secret mission: to destroy the faery who murdered her mother. But when she learns she’s a Falconer, the last in a line of female warriors and the sole hope of preventing a powerful faery population from massacring all of humanity, her quest for revenge gets a whole lot more complicated. The first volume of a trilogy from an exciting new voice in young adult fantasy, this electrifying thriller blends romance and action with steampunk technology and Scottish lore in a deliciously addictive read.