‘What are you thinking, Amy?’ The question I’ve asked most often during our marriage, if not out loud, if not to the person who could answer. I suppose these questions stormcloud over every marriage: ‘What are you thinking? How are you feeling? Who are you? What have we done to each other? What will we do?’

Just how well can you ever know the person you love?

This is the question that Nick Dunne must ask himself on the morning of his fifth wedding anniversary when his wife Amy suddenly disappears. The police immediately suspect Nick.

Amy’s friends reveal that she was afraid of him, that she kept secrets from him. He swears it isn’t true. A police examination of his computer shows strange searches. He says they aren’t his. And then there are the persistent calls on his mobile phone.

So what really did happen to Nick’s beautiful wife? And what was in that half-wrapped box left so casually on their marital bed?