Returning to her gothic childhood home in the wake of her estranged twin's disappearance, Cat uncovers long-held secrets involving her sister's left-behind clues and a mysterious treasure hunt. Cat lives in Los Angeles, far away from the imposing gothic house in Edinburgh where she and her estranged twin sister, El, grew up. As girls, they invented Mirrorland, a dark, imaginary place under the pantry stairs full of pirates, witches, and clowns. El...