Kilometre-long trenches close in Sarajevo on all sides . The city has been besieged for more than one thousand days. Alija, Graca and Hidaet , each belonging to a different age group and profession are three of the city's defenders , three " employees " of the war , who, on alternate days , spend 24 hours in the front line . 24 hours of deep silence and interminable waiting , broken by the occasional order , by enemy attacks and by the shift change .