'I can imagine you at forty,' she said, with malice in her voice. 'I can picture it right now.' He smiled without opening his eyes. 'Go on then.' 15th July 1988. Emma and Dexter meet for the first time on the night of their graduation. Tomorrow they must go their separate ways. So where will they be on this one day next year? And the year after that? And every year that follows? Twenty years, two people, ONE DAY.