The instant New York Times bestseller In this twisty psychological thriller from the #1 New York Times bestselling author of THE CELLAR Ivy finds out that her twin sister Iris is trying to push her out of her own life--and might be responsible for their mother s death. After their parents divorced 10-year-old twins Ivy and Iris were split up--Ivy lived with Dad Iris with Mom. Now after a tragic accident takes their mom s life the twins are reunited and Iris moves in with Ivy and their dad. Devastated over Mom s death Iris spends the first few weeks in almost total silence--the only person she will speak to is Ivy. Iris feels her life is over and she doesn t know what to do. Ivy promises her twin that she can share her life now. After all they re sisters. Twins. It s a promise that Iris takes seriously. And before long Ivy s friends her life at school and her boyfriend Tyler fall under Iris s spell. Slowly Ivy realizes she s being pushed out of her own life. But she s just being paranoid right? And Mom s accident was . . . just an accident. Right? It s not like she--or Dad--or Tyler--are in any danger. . . .