The Great War is over and a long-awaited engagement is on, but all is not tranquil at Downton Abbey as wrenching social changes, romantic intrigues, and personal crises grip the majestic English country estate. As other great houses are crippled psychologically and financially in the wake of World War I, Robert, Earl of Grantham, sticks to his duty to maintain Downton more firmly than ever. But in this changing landscape nothing is assured, and could it be that even the war-weary Crawleys must fight a new battle to safeguard their beloved Downton?
Cora’s mother arrives for Matthew and Mary’s wedding. New footman Alfred strives to meet Carson’s high standards, under the watchful eye of his aunt O’Brien.
Hoping for a bailout from her American grandmother, Mary makes sure Downton puts on a bigger show than ever before. Mrs Hughes gets worrisome news. Thomas disapproves of O'Brien's attempts to boost Alfred's progress.
Edith's big day finally arrives, but will the family be convinced that Strallan's age does not matter? Mary takes matters into her own hands - but the price could be high.
Branson's political views land him in hot water and Sybil's loyalty is tested to the limit. Ethel is torn between head and heart as she makes a decision about her son's future.
An exciting offer for Edith divides opinion. Isobel throws Ethel a lifeline. New maid Ivy is attracting attention below stairs, and Alfred's interest is resented by Daisy.
Tempers fray as Isobel's kind gesture backfires. Branson's decisions are put under scrutiny. As Bates's chance of freedom slips away, he goes to extreme lengths.
Anna's patience is finally rewarded. Edith has an unexpected admirer. Matthew refuses to back down over his concerns. Branson's plans for the christening cause consternation.
There's excitement in the house and village as the annual cricket match approaches, and the event brings out Robert's competitive side. Violet's great-niece Rose shows up but a trip to London reveals there is more to her than meets the eye. Matthew and Mary look like they are keeping secrets from each other. Thomas finds out that his future lies in Carson's hands.