When young Joe Ellis leaves the workhouse to take up an apprenticeship at the local slate mine in the summer of 1914, his future life seems settled. Even the outbreak of war with Germany that August appears unlikely to make any difference to the small Welsh village where he lives with his uncle. As Joe learns his trade, starting as a mere 'rubbler' before working underground in his uncle's bargaining team, he faces some exciting challenges and dangers. But the shadow of the the war is growing, with newspaper reports, a letter from the Front and a local recruiting drive. Meanwhile, financial problems raise their head at home and when a foolish prank results in Joe and his friend Glyn being suspended without pay, the pair decide to enlist, in spite of being under age. Over in France, they find themselves, much to their disgust, digging tunnels once again, this time under enemy lines, before coming under intensive machine-gun fire at the Battle of Aubers Ridge where Joe is wounded. Discovered to be under age, Joe is sent back home where he faces a dilemma. Still haunted by the trenches, should he go back to the quarry to please his uncle, or accept a more appealing offer above ground? The decision must be made soon.