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: heir Matthew Crawley and footman Thomas Barrow are off fighting, while Lady Grantham and Isobel Crawley are squabbling over whether Downton should be used as a hospital. Lady Mary is seeing a wealthy newspaper magnate while Lady Edith becomes much warmer and Lady Sybil seeks to ingratiate herself...

1922. Six months after Matthew's tragic death, his loss is still felt throughout Downton Abbey. Mary struggles to face a new future with her fatherless child, and is encouraged by the family to pick up the pieces. Accepting a new role on the estate, the now-eligible Mary also finds herself the reluctant object of attention from a number of eager suitors. With the twenties in full swing and the tides of change sweeping through Downton, Rose's continued...

As World War I winds to a close, two men, Dr. William Rivers, a psychologist whose dedicated healing sends men back to the brutal front, and Billy Prior, a shell-shocked soldier determined to rejoin the final English offensive, are profoundly affected by the events of the era.

It is the spring of 1918, and Britain is faced with the possibility of defeat by Germany. A beleaguered government and a vengeful public target two groups as scapegoats: pacifists and homosexuals. Many are jailed, others lead dangerous double lives, the "the eye in the door" becomes a symbol of the paranoia that threatens to destroy the very fabric of British society.