1918. As the Armistice bells ring out across the world to celebrate the end of the Great War, a silent killer makes its way home with the soldiers. The Spanish Flu will kill up to one third of the world’s population, more than both world wars combined. From the soldier who carried the virus to the Western Front, to the doctor who started the fightback, follow the compelling human stories behind this seismic chapter of history. With new evidence revealed for the first time, this documentary tracks the dramatic race to stop the pathogen spreading. The clock is ticking.