Italy, 1944: Florence is occupied by Nazi forces. The Italian resistance movement has not given up hope, though -- and neither have thirteen-year-old Paolo and his sister, Costanza. As their mother is pressured into harboring escaping POWs, Paolo and Costanza each find a part to play in opposing the German forces. Both are desperate to fight the occupation, but what can two siblings -- with only a bicycle to help them -- do against a whole army?