Bella can't wait to be married to her fiancée Sidney, and dreams of the day she will walk up the aisle to be given away by her widowed father, with her bookish sister Alice as her bridesmaid. Their lives are disturbed when they receive a letter from their fifteen-year-old cousin Millie. Taken in by her austere aunt and uncle when her parents were killed in an accident, Millie says she is being badly treated and pleads to be rescued. When the two sisters take a trip to find out the truth, things take a troubling turn. Millie is brought home to live with them, her only possessions her ill-fitting clothes and a tatty suitcase. But soon they are questioning this act of kindness. Does their teenaged cousin just need some love and kindness? Or is she a troublemaker, with only mischief and malice on her mind?