"Ferociously entertaining. A novel like a triathlon: part evil-twin thriller, part howdunit (or did-she-do-it?), part juicy family drama. Drop Knives Out and Double Indemnity into the blender, shake some Dead Calm over the froth, power it on, and you’ve got a cocktail like The Girl in the Mirror—fresh, flavorful, and utterly intoxicating." —AJ Finn, #1 New York Times bestselling author of The Woman in the WindowWritten with the chilling, twisty suspense of The Wife Between Us and Something in the Water, a seductive debut thriller about greed, lust, secrets, and deadly lies involving identical twin sisters.Twin sisters Iris and Summer are startlingly alike, but beyond what the eye can see lies a darkness that sets them apart. Cynical and insecure, Iris has long been envious of Summer’s seemingly never-ending good fortune, including her perfect husband Adam.Called to Thailand to help her sister sail the family yacht to the Seychelles, Iris nurtures her own secret hopes for what might happen on the journey. But when she unexpectedly finds herself alone in the middle of the Indian Ocean, everything changes. When she makes it to land, Iris allows herself to be swept up by Adam, who assumes that she is Summer.Iris recklessly goes along with his mistake. Not only does she finally have the golden life she’s always envied, with her sister gone, she’s one step closer to the hundred-million-dollar inheritance left by her manipulative father. All Iris has to do is be the first of his seven children to produce an heir.Iris’s “new” life lurches between glamorous dream and paranoid nightmare. On the edge of being exposed, how far will she go to ensure no one discovers the truth?And just what did happen to Summer on the yacht?Only Iris knows . . .