Sirens / Joseph Knox.

Isabelle Rossiter has run away again. When Aidan Waits, a troubled junior detective, is summoned to her father's penthouse home - he finds a manipulative man, with powerful friends. But retracing Isabelle's steps through a dark, nocturnal world, Waits finds something else. An intelligent seventeen-year-old girl who's scared to death of something. As he investigates her story, and the unsolved disappearance of a young woman just like her, he realizes Isabelle was right to run away. Soon Waits is cut loose by his superiors, stalked by an unseen killer and dangerously attracted to the wrong woman. He's out of his depth and out of time.How can he save the girl, when he can't even save himself?