September 2009 sees the 70th anniversary of the outbreak of World War II and the launch of Operation Pied Piper, a campaign to evacuate over one million people - mostly children - from British cities perceived to be at risk from bombing by the Luftwaffe. Over the course of the war, the number of evacuees rose to nearly 3.5 million. Though evacuation was not compulsory, billeting was, giving rise to hundreds of thousands of children being imposed on families hundreds of miles away from their own homes. When they left the big cities, they didn't know where they going or how long they'd be away. This series follows a number of evacuees, now in their 70s and 80s, as they retrace their steps to their old billets and reunite with long-lost friends and foster families.