In episode one, as war breaks out, Daniel Mays plays Reg Evans, a cockney lad and one of the first to volunteer to fight. He found himself a hero in the trenches, his journey told through moving letters to his anxious mother at home. Matthew McNulty plays Alan Lloyd, an upper-crust young man from Birmingham who joined the army in the same month he was married: his letters to his new wife from the battlefields of Ypres reveal the shock of a generation of young men coming to terms with a war more terrible than anyone had foreseen. And Myanna Buring plays Dorothy Lawrence, a young woman determined to find a part she could play in the war… and who set off on her own to the trenches, undercover as a war correspondent. Adam Byron plays James Butlin, a young Oxford University student, whose letters indicate initial positivity on joining the conflict disintegrating into despair as the reality of trench warfare takes its toll.