Downton Abbey season 6
Season 6 of Downton Abbey, which will pick-up six months after the events in season 5, promises "more drama" on the show ITV

Fans have witnessed ups and downs in the lives of the members of the Crawley family with immense curiosity, but the longest running British drama will be drawing curtains on Downton Abbey post its sixth season. The drama surrounding Downton will return with its final season on 20 September on ITV.

Season 6 is set in 1925, around six months after the events of the season 5 finale. But the upcoming season sure promises more drama, "infused with the prospect of happy endings for its lead characters".

In the latest trailer unveiled by the network, Lord Grantham is seen bidding an emotional farewell to his loyal butler Mr. Carson. He says, "If I could stop history in its tracks, maybe I would. But I can't, Carson, for neither you nor I can hold back time."

In another scene from the promo, Anna (Joanne Froggatt) is seen reminiscing her past along with Lady Mary (Michelle Dockery) and tells her, "We have had our moments, haven't we my lady?" To which, Mary replies, "We certainly have."

Meanwhile, Dockery dished about Lady Mary's fate in the final season in an interview with Harper's Bazaar. She says: "How Mary is and what happens is quite shocking."

The actress adds, "There are always twists and turns in the plot -- there are every year -- but this year particularly, there's a bit of a U-turn that happens with Mary, and it's amazing."

Lady Mary has to make a choice about her tumultuous love life in the final season. After losing her husband Mathew in season 3, Dockery's character spent season 4 grieving, and season 5 trying to get over her past, but it is about time she selects a suitor for herself.

Further, Hugh Bonneville who plays Lord Grantham/Robert claims that the final season has the end of an era flavour to it.

"This final season very much has a flavor of the end of an era, you know, quite literally," Bonneville shares and adds, "And it's brought home to [the characters] when we go to visit a neighbor in the county who is literally having to sell the family silver... and the entire family sees that, and sees the writing on the wall. "

Bonneville explains, "You adapt or you die, and I think Robert -- [the] dinosaur that he has been at times -- ultimately, whether he's dragged, kicking and screaming by Mary or by his mother or by Cora, does adapt, does see that change is necessary."

Downton Abbey season 6 premieres on 20 September in the UK and on 3 January 2016 in the US.