Having found the safety of the Greenland bunker after the comet Clarke decimated the Earth, the Garrity family must now risk everything to embark on a perilous journey across the wasteland of Europe to find a new home.

When Mary finds herself at the center of a public scandal and the family faces financial strife, 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.

讲述在一场国际危机期间，这名美国外交官既要应对身为驻英大使的重任，又要处理与政坛明星之间紧张的婚姻关系。