In the early 20th century, the Crawley family and their domestic staff prepare for a significant event: a royal visit from King George V and Queen Mary. The anticipation of this honor sets in motion a flurry of activity at the grand Yorkshire country house Downton Abbey. The Earl and Countess of Grantham, along with their daughters Mary and Edith, their in-laws, and the Dowager Countess, are all invested in presenting the estate at its finest. Below stairs, Mr. Carson, the retired butler, is called back into service to oversee the meticulous arrangements, much to the chagrin of the current butler, Thomas Barrow, who feels his authority is being undermined.

The royal visit, however, brings its own set of upheavals as the Downton Abbey servants find themselves pitted against the royal staff, who aim to supplant them in their own domain. While the household staff endeavors to defend their turf, personal and social politics come into play. The family grapples with their changing circumstances, social expectations, and personal ambitions, illuminating the tensions and transitions of the post-Edwardian era. As preparations intensify, alliances are formed, secrets emerge, and the characters confront challenges that threaten the fabric of their traditional way of life, testing loyalties and inspiring them to contemplate their future in an ever-changing world.