Hala's mobile phone contains her entire world. Having left war-torn Aleppo for a new life in Germany, it's her only connection to her past.
Filmmaker Marcel Mettelsiefen followed one family for three years as they struggled to survive in besieged Aleppo, eventually becoming refugees and fleeing to Germany.
Watch part 1, Children on the Frontline on All 4: http://bit.ly/1eoNelB
Watch part 2, Children on the Frontline: The Escape on All 4: http://bit.ly/1NqkH48