A Knock at the Door'Riveting, twisty as all hell, and very, very clever, A Knock at the Door is a rollercoaster ride of brilliance. TW Ellis is a superb thriller writer' SARAH PINBOROUGH They ask for your husband. They just want to talk. THEY'RE LYING. Your husband isn't who he says he is, say the people at your door. Come with us. Don't trust them, says a voice on the phone. Run. Who would you believe? In this terrifying first psychological thriller by bestselling