Gwenllyn Lyons has been raised by her grandmother, in an elegant cottage set in the hills above the Wye Valley. One afternoon, as she and her grandmother return from town, they come across a man lying injured and unconscious by the river bank. They take him home and nurse him until he recovers but nothing seems to help him regain his lost memories - he has no idea who he is, or where he has come from.

Over the long hot summer they spend together, Gwenllyn realises that she can't imagine what it would be like without this handsome young man in her life. As her love for the mysterious stranger grows, she cannot help rejoicing when she realises he feels the same way about her. Gwenllyn's only fear is that some day his past may come to haunt them - a different life, where another woman might be waiting for him. Will she ever have the happiness of being a bride, or will she always be the other woman?