Twenty three years ago, Maudie Sampson’s childhood friend Jessica disappeared on a family holiday in Cornwall. She was never seen again. In the present day, Maudie is struggling to come to terms with the death of her wealthy father, her increasingly fragile mental health and a marriage that’s under strain. Slowly, she becomes aware that there is someone following her: a blonde woman in a long black coat. As the woman begins to infiltrate her life, Maudie realises no one else appears to be able to see her.