The Great War is over and a long-awaited engagement is on, but all is not tranquil at Downton Abbey as wrenching social changes, romantic intrigues, and personal crises grip the majestic English country estate. As other great houses are crippled psychologically and financially in the wake of World War I, Robert, Earl of Grantham, sticks to his duty to maintain Downton more firmly than ever. But in this changing landscape nothing is assured, and could it be that even the war-weary Crawleys must fight a new battle to safeguard their beloved Downton? 

The Great War rages across Europe, and not even the serene Yorkshire countryside is free from its effects. The men and women of Downton are doing their part both on the front lines and the home front, but the intensity of war only serves to inflame the more familiar passions: love, loss, blackmail, and betrayal.