The beloved Crawleys and their intrepid staff prepare for the most important moment of their lives. A royal visit from the King and Queen of England will unleash scandal, romance and intrigue that will leave the future of Downton hanging in the balance.

The Crawley family goes on a grand journey to the south of France to uncover the mystery of the dowager countess's newly inherited villa. Meanwhile, a Hollywood director seeks to film his latest production at Downton.

When Mary finds herself at the center of a public scandal and the family faces financial trouble, the entire household grapples with the threat of social disgrace. The Crawleys must embrace change as the staff prepares for a new chapter with the next generation leading Downton Abbey into the future.