Almost four years into Russia’s invasion, keeping Ukraine’s lights on has become a battle of its own. It’s a moving front line that Moscow has tried and failed to break. One reason is the tireless work of utility engineers. They repeatedly repair transformers, switchyards, and power lines that Russia strikes again and again, using bomb-laden drones to hunt workers’ trucks near the border. At least 160 energy workers have been killed and more than 300 wounded since the war began. Yet tens of thousands still head out each day, often driven by a quiet mission to bring light through the darkness.