A year after one of their identical twin daughters, Lydia, dies in an accident, Angus and Sarah Moorcraft move away, hoping to put together the pieces of their shattered lives. But when their surviving daughter, Kirstie, claims they have mistaken her identity – that she, in fact, is Lydia – their world comes crashing down once again. Sarah finds herself tortured by the past – what really happened on that fateful day one of her daughters died?