When, on the night of their wedding, Ned asks his new wife Rose to promise that she will never leave him, Rose is quick to give her aristocratic husband her word: keeping it, however, proves harder.

For even on the day when she has promised to forsake all others, Rose's heart is with the true love of her life, Mylo, the penniless but passionate Frenchman who, within five minutes of their meeting declared his love and asked her to marry him.

Whilst Rose remains true to her promise never to leave Ned, not even the war, social conventions, nor the prying of her overly inquisitive and cheerfully immoral neighbours, can stop her and Mylo from meeting and loving one another.