A crisis of inheritance threatens to displace the resident Crawley family, in spite of the best efforts of the noble and compassionate Earl, Robert Crawley (Hugh Bonneville); his American heiress wife, Cora (Elizabeth McGovern); his comically implacable, opinionated mother, Violet (Maggie Smith); and his beautiful, eldest daughter, Mary, intent on charting her own course. Reluctantly, the family is forced to welcome its heir apparent, the self-made and proudly modern Matthew Crawley (Dan Stevens), himself none too happy about the new arrangements.
Downton Abbey's Granthams and their family of servants have already weathered scoundrels, scandals, and a momentous succession crisis. But by November, 1916, the Great War has rendered everything — and everyone — changed. Even Downton Abbey itself, like its residents, has risen to the call of duty and transformed. At the war front, life intensifies for Downton's young men in the face of untold horrors. Meanwhile, at Downton, war makes new and often unjust demands.