The story of decorated WW1 hero and renowned British poet Siegfried Sassoon (Jack Lowden), who became one of the "Bright Young Things" of London society in the 1920s. Haunted by war and put off by the decadent behavior of his contemporaries including renowned composer Ivor Novello (Jeremy Irvine), he remained determined that the legacy of the young men with whom he served would not be forgotten.