In this moving tribute to the teenage heroes of the Great War, Fergal Keane unearths the most powerful stories of Britain's boy soldiers. With as many as 250,000 boys under the age of 18 having served in the British Army during World War I, and with every tenth volunteer lying about his age, Fergal looks to find out what made them enlist. Was it motivated by patriotism or the spirit of adventure? Fergal follows the children into the trenches to see how they coped with the reality of war. He explores how, as the casualties began to mount, a movement grew in Britain to get them home. Fergal also meets the children and grandchildren of these former boy solders, uncovering heartrending, but often uplifting, stories and taking them on an emotional journey to the places where their ancestors trained and fought.