The thorny relationship between two estranged sisters powers this atmospheric thriller from Quinn (Blood Sisters). Meg catches cheaters for an L.A. casino and spends the money she makes on her drug and alcohol habit. Meanwhile, her older sister, Haley—with whom Meg has long been out of touch—has become a famous actress, whose own substance problems have made her a tabloid fixture. Meg has just nabbed her latest mark when she learns that Hayley has committed suicide at “The Clinic,” a luxury recovery center on the grounds of a former mansion on the Oregon coast. Refusing to believe her sister could kill herself, Meg checks herself into the Clinic in search of answers. As she learns of the patients’ heavily restricted movements and devotion to the menacing Dr. Lutz, she uncovers a sinister conspiracy that reframes her understanding of her late sister. Quinn smartly rotates between Meg’s viewpoint and that of Cara, a former L.A. hotel manager who was invited to manage the Clinic by an unknown recruiter ; though Cara is ancillary to the main plot, her insights into the Clinic’s operations provide tension and dramatic irony. Quinn’s fans will be rapt. Agent: Piers Blofeld, Sheil Land Assoc. (Jan.)