Historian Max Hastings makes the case that Britain was right to fight the First World War, pushing back against the century-old consensus that it was a senseless slaughter. He traces the alliances and rivalries that pulled Europe into war in 1914, then follows the fighting through the trenches, tracking how new weapons like tanks and aircraft changed the battlefield. Letters, diaries, and personal accounts carry the human cost, giving voice to soldiers at the front and the families waiting at home. Hastings draws on his own work from the series The Great War to argue that the war reshaped politics and society in ways that mattered, from the collapse of European empires to the eventual spread of democracy. Made for BBC Two, the film frames itself explicitly as a rebuttal to historians who call the war futile, setting out to defend the choices of 1914 rather than simply narrate them. The argument, not the battle footage, is the point.