Manchester, 1940. They called it the Christmas Blitz but for Jess Delaney, the German bombs meant being locked in the cellar by her feckless, tarty mother, Lizzie - nothing festive there. If it weren't for her friend Leah, Jess wouldn't celebrate Christmas at all. Things go from bad to worse when Lizzie is imprisoned for shoplifting and Jess is sent to live with her uncle, a dishonest bruiser of a man and black marketeer, who treats her like a slave. The Sally Army offers her, literally, salvation, and a chance to develop her natural musical talent by learning to play the trumpet. When a young airman dares her to play at an afternoon tea dance, Jess rises to the challenge and is soon playing in a band. But Uncle Bernie has never forgiven his niece for refusing to join him in his thievery, and threatens to take away all her hard-won independence.