East London, 1940. Prue Carmichael never dreamed that she'd end up working at a railway yard. But when her reverend father is called up to Stepney, she and her family are uprooted from their country home for a new life in the turbulent city. Determined to help with the war effort, Prue signs up for work and soon becomes intrigued by handsome train engineer Jack Quinn. But as the spark between them grows apparent, so does his troubled past - a past...