In this final episode of series one, many changes are taking place within the Crawley household as the First World War looms. His Lordship is stunned to discover that Cora is pregnant, news which leaves Cousin Matthew wondering what his future will be if the baby is a boy.
Meanwhile, O'Brien mistakenly believes that she is about to be fired from her job while Thomas takes steps of his own to ensure his success when the hostilities inevitably break out. Lord Grantham has some devastating news for the guests at the annual Downton Abbey garden party.
Lady Sybil expresses her interest in politics to Lord Grantham, who isn't at all pleased to hear of her venture to the debate, and things take a drastic turn when she's injured at the bi-election results. Meanwhile, Lady Mary and Matthew continue to get closer, leading to a proposal of marriage, much to Cora and Violet's delight. However, the events surrounding Mr. Pamuk's death may put a spanner in the works.
Thomas continues his campaign to get rid of Mr. Bates from Downton with the help of O'Brien and a misguided Daisy by accusing him of stealing the wine from the cellar.
The village hall is being utilized to make preparations for the annual Downton Village Flower Show. Sybil takes Gwen to another job interview. Daisy is still reeling from seeing what happened to Mr. Pamuk. And Edith finds a way to get her own back on her sister, Mary.
Two men vy for Daisy's affections, wanting to take her to the fair, while Sybil helps Gwen in her search for a new job. Violet has a favour to ask of Matthew. Mrs. Hughes takes an evening off to spend time with an old flame.
The reason behind Gwen's secret correspondence is revealed, much to the surprise of the staff and Cora's matchmaking attempts fail when Mary takes a liking to another man from foreign parts who is intent on sweeping her off her feet. Meanwhile, Bates is desperate to cure his limp and goes to some extreme measures to do so.moreless
The arrival of Matthew and Isobel Crawley causes a stir at Downton Abbey. Matthew struggles to settle down, while Isobel doesn't make a good first impression on Violet. Elsewhere, the past catches up with Carson when he is blackmailed by a conman and Gwen appears to be corresponding with someone in secret.moreless
News of the Titanic's sinking has just reached Downton Abbey, causing much chaos within the family as Lord Grantham has three daughters and no male heir. His only two heirs went down with the ship, including Patrick Crawley, who was to marry Lady Mary, the Earl's eldest daughter. With both heirs now dead, the Crawley girls must find husbands of their own as the entire estate is entailed away from the female line; however, perhaps there is hope after all as Matthew Crawley, a third cousin, once removed is now heir to the title and the estate. The Dowager Countess of Grantham and Mary's mother, Cora, make it quite clear that Mary is to try her hardest to secure cousin Matthew as a husband in order to save everything.moreless