Rise of the Melody by Wendy Higgins

From the bestselling author of the YA paranormal Sweet Evil series comes a modern fantasy romance of mystery with Celtic and Gaelic mythology.

Seventeen-year-old Colette “Letty” MacIntyre has everything going for her: a great life with her Aunt Lorna in Brooklyn, a promising singing career, and enough distractions to forget the tragic disappearance of her parents. She’s banking on a bright future in the city until strange things begin to happen. People are suddenly having peculiar reactions to her singing voice, and a giant wolfhound starts following her like a lost puppy. But the cherry on top is when the mayor of her long-forgotten birthplace, Benn Shehan, a mountainous island off the craggy northern coast of Maine, shows up on her doorstep with an impossible revelation: the Gaelic folklore she grew up hearing is real. Letty is the last land siren on Earth…and he needs her help.
An escaped kelpie—a monstrous water horse—is terrorizing Benn Shehan, and Letty’s voice is the only thing that can stop it. Despite the shock at learning her heritage, Letty returns to the island, which is filled with as much mystery as it is fog. She wants answers to her parents’ disappearance as well as a chance to prove herself. But in a race of mighty druids and formidable Scottish witches, Letty’s power is an anomaly, feared and reviled by the mystic community. Her lineage must be kept secret. It becomes even harder to fulfil these tasks when a new enemy threatens her—an alluring, powerful druid boy filled with darkness who would just as soon kill her as kiss her.

Will her deadly melody be enough to save the town and herself?