Shadow of the Moon by Rebecca York

Lance Marshall, a journalist with werewolf abilities, has eyes and instincts sharpened for danger. When Savannah Carpenter’s sister falls into a coma after frequenting the ultra-exclusive club known only as “The Castle,” Savannah fears the club’s decadent secrets are darker than they appear. Disguised as lovers, Savannah and Lance infiltrate the club’s gates—only to discover a monstrous evil lurking in its heart. As the physical attraction between them blazes, so does the peril. Shadow of the Moon is a sultry, suspense-driven romance where every secret uncovered inches them closer to both salvation and disaster.