The Crawley family, aristocrats overseeing the grand English estate of Downton Abbey, faces a pair of significant changes that threaten to disrupt their traditional way of life. As the modern era encroaches upon them, the family and their servants are first taken aback when a film crew arrives at Downton, seeking to use the picturesque setting for a silent movie. The intrusion of Hollywood glamour brings both excitement and upheaval to the residents, with some embracing the opportunity more than others. The dynamics within the house also begin to shift as the staff and family members interact with the film's cast and crew, each affecting the other's perspective on the swiftly changing world outside their estate's walls.

In parallel, Lady Violet Crawley, the Dowager Countess of Grantham, reveals she has unexpectedly inherited a villa in the south of France from a mysterious past acquaintance. This revelation leads to questions and some excitement among the family, sparking a journey to the French Riviera. The expedition overseas promises not only to uncover details of the Dowager's secretive past but also to expose the Crawleys to different cultures and ways of life. As some family members venture abroad to explore this new inheritance, those remaining at Downton grapple with the challenges and hilarity of hosting a bustling film set within the formerly serene estate.