Two sisters. One promise. But will their bond survive the test of time? 1936. After their father loses their family fortune, and their mother locks herself away, sisters Grace and Clementine are left to raise themselves in a grand London house that is slowly falling apart. Each of them is determined to one day restore their money and the family name and makes a promise to do just that.Clementine dreams of being a celebrated ballerina who will tour the world. She is adamant she won't put her fate into a man's hands but take charge of it herself instead.While Grace sees security in a good marriage. Their new eligible American neighbour - with wealth, charm, and looks - seems like the perfect match.But when Clementine falls unexpectedly in love, it throws both sisters' lives into turmoil, and forces each of them to ask if they are prepared to break their promise for a chance at true love...