The Great War unsettles life at Downton and surprising news about Matthew rocks the family. New maid Ethel irritates O'Brien - and Bates returns with devastating news for Anna.

Carson is finding it tough maintaining standards in the house, and the suicide of a young officer prompts Isobel to suggest converting Downton Abbey into a convalescent hospital.

After Downton is turned into a convalescent home for wounded officers, Matthew brings a general to visit, but Branson has a surprise in store. And is Lavinia hiding something?

Tensions flare between Isobel and Cora. Ethel's flirtation with Major Bryant lands her in hot water. There is worrying news about Matthew. Branson declares his feelings for Sybil.

Robert receives some shocking news from the front. Daisy's relationship with William moves faster than she would like. Vera threatens to expose old secrets.

Carlisle threatens to ruin Mary if she jilts him. A major comes to stay - but is he really who he claims to be? Bates learns that Vera has succeeded in scuppering the divorce.

How long can Sybil and Branson keep their secret? Carlisle puts Anna in a difficult position, Bates is left reeling from the news about Vera, and Thomas embarks on a new scheme.

With the wedding approaching there is excitement in the air, but will Branson's plans rattle everyone? A decisive Anna forces Bates to think about their future.

The cast and creators of the award-winning drama series tell the story of the show from the inside. The actors talk exclusively about their characters and the gripping storylines, giving the audience a real insight into the romance and conflict portrayed in the series. There is also behind-the-scenes footage from key locations - the historic Ealing Studios in London where the 'below stairs' scenes are shot and the fabulous Highclere Castle in Berkshire, site of most of the 'above stairs' scenes. Plus there is a look at the filming of the dramatic opening of the second series, set during the Battle of the Somme and shot on location near Ipswich.

As we return to Downton Abbey, the household is bustling with all the Christmas preparations. But, there's tension in the air between Sir Richard Carlisle, Lady Mary and Matthew... And, Bates' trial casts a dark cloud over the festivities. Will he be found guilty of the murder of his wife?