The air in Marcoing, France, was thick with the scent of sulfur and rotting earth on September 28, 1918. Henry Tandey, a British private from Warwickshire, was hunkered down in a water-logged trench as the Great War neared its bloody end. He was already a decorated hero, a man who had survived the slaughter of the Somme and Passchendaele through sheer courage. The sky was a bruised shade of purple as the British launched a fierce assault against the crumbling German lines near the canal. Tandey was a crack shot, his Enfield rifle feeling like an extension of his own battle-hardened and weary body. Through the thick smoke of a nearby explosion, he saw a wounded German soldier stumbling out of the grey mist. The man was unarmed, limping painfully, and covered in the filth of a hundred lost battles and broken dreams. Tandey raised his rifle, his finger tightening on the cold steel trigger as he lined up the perfect shot. He could see the man’s exhausted face, eyes wide with the realization that his life was about to end right there. But Henry Tandey was a man of honor who believed that you didn’t shoot a wounded, retreating soul in cold blood. He slowly lowered his rifle, nodding to the German soldier as a silent gesture of mercy in the middle of hell. The German soldier nodded back in gratitude, clutching his side as he disappeared back into the safety of the fog. Tandey didn’t know he had just made a decision that would haunt the rest of his life and the entire world. That moment of mercy was a tiny spark that would eventually set the whole planet on fire in twenty years.
