Sarah Phelps’ gripping drama tells the story of World War One’s front line medics – their hopes, fears, triumphs and tragedies. The tented field hospital in which they work is a frontier; between the battlefield and home front, but also between the old rules, hierarchies and a new way of thinking. Oona Chaplin (The Hour, Quantum Of Solace), Hermione Norris (Spooks, Cold Feet), ...