'Downton Abbey' Season 6 cast members
Downton Abbey cast members and crew pose for the media at a hotel in central London, Britain August 13, 2015. Downton Abbey's final season is due to premiere in September. Reuters/Dylan Martinez

It is time for the people living upstairs and below stairs to pack their bags, as the curtain falls on “Downton Abbey” this Christmas. The swansong season of this British period drama premieres on Sept. 20 in the U.K., and according to creator Julian Fellowes, fans should not expect a happy ending for all the characters in "Downton Abbey" Season 6.

The final season is set in 1925 -- the period when the reins of power were slipping from the hands of the British aristocrats, and the middle class was becoming a force to reckon with. The final season of “Downton Abbey” is expected to show that shift in power and the dwindling influence of Crawley family. Robert Crawley (Hugh Bonneville), Earl of Grantham, will be forced to adopt a new lifestyle sans the servants below stairs. Probably this statement from a new maid sums up the final season of “Downton Abbey”: "You're going down and we're going up." The new maid tells that to Lady Mary (Michelle Dockery), according to Independent.

The first episode of the final season picks up six months after the events of “Downton Abbey” Season 5, opening with new developments -- some expected and some unexpected. Here are the top six spoilers from “Downton Abbey” Season 6:

Tom Branson (Allen Leech) sticks to his decision of moving out of Downton, and in the premiere episode, he is in Boston with his daughter, Sybil, and appears lonely. It is confirmed that Branson will return to Grantham estate, but it is not known whether it is for a brief visit, or he will be returning for good.

Lady Mary takes over the management of the Downton estate, and not everyone approves of that, including Lady Violet Crawley (Maggie Smith), according to Independent. Henry Talbot, played by Matthew Goode, is returning and is likely to be Lady Mary's pontential love interest.

Lady Edith (Laura Carmichael) moves to London. She successfully runs her late partner’s, Michael Gregson , magazine and becomes part of London's intelligentsia, and she also meets a worthy suitor in London. However, she and her sister, Lady Mary, continue to clash, and their different "town and country lifestyles" add fuel to their already troubled relationship, Independent reported.

Mr Carson (Jim Carter) and Mrs Hughes (Phyllis Logan) get married. But before saying their wedding vows, they are likely to discuss their sex lives.

Isobel (Penelope Wilton) and Lady Victoria continue to have their battle of wits. Independent reported that the "restructure of the local hospital becomes a point of contention" between them.

There is a new member downstairs -- the refrigerator, and some of the old members get elbowed out.

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