Forensic psychologist Claire Markwood has answered her fair share of heart-stopping phone calls, but none quite as chilling as the one informing her that her sister, Darcy, is missing. Claire rushes to the butterfly sanctuary where Darcy has been working, prepared to do what she does bestwork the clues. But Darcy, along with her car and some of the sanctuarys rarest species of butterflies, have seemingly vanished without a trace.Amid a flurry of mysterious leads and dead ends, Claire and her criminal-lawyer husband, Nick, turn to friends and colleagues, desperate to tap every resource at their disposal. But the deeper they dig, the more unsettling the case becomes, dredging up old family secrets that shake the foundation of everything Claire thought to be true. And by the time this latest deadly threat is done with them, nothing will ever be the same.