THE GRIPPING LOCKED-ROOM DYSTOPIAN THRILLER FOR FANS OF EMILY ST. JOHN MANDEL AND ANDREW HUNTER MURRAY 'A testament to the power of the written word' THE TIMES'Unsettling and thought-provoking' CLARE MACKINTOSH This isn't the world you know.This isn't the story they expect. Twins Ana and Nan believe they keep no secrets from one another. They both think they know what pushed their mother to suicide.Only one of them does. They both think they know how their revenge plot will play out.Only one of them does. They both think they know what's really happening at the library.Only one of them does. But neither of them know what will unfold once the library doors close and the chaos begins. No one's getting out. But the truth finally might . . .