In Lisa Unger’s hurricane of a thriller, Florida housewife Annie Powers faces down demons from her past, among them a youthful love affair with her hunky stepbrother, a sadistic murderer who dragged her along on a bloody cross-country crime spree until he was caught and killed. Or was he? Annie has her doubts. She also has hallucinations, a dodgy shrink, suspicions about her ostensibly devoted husband, and occasional inklings that she too might harbor homicidal impulses. It’s hard to find your footing in Black Out, but it’s also impossible to extract yourself until the last page. B+