On Dec. 12, 2013, shortly before the sun dipped behind the mountains and left a handful of modest stone-built homes and grazing goats in a fading silhouette, the ground shook. Across the valley, black smoke billowed into the sky. In the moments it took for the repeated explosions to echo from beyond the dry riverbed, the lives of scores of men, women and children in the Yemeni village of Jishm were shattered....