Michelle Dockery, Allen Leech

Pull out your dancing shoes, because Downton Abbey will be entering the Jazz Age.

[Warning: The following contains major spoilers from the past three seasons of Downton Abbey. If you haven't caught up yet, read at your own risk!]

It's been months since fans reeled from that shocking Christmas episode that also rocked the Crawley family, and now they're moving into the 1920s with new babies, suitors and even a musician or two. The story picks up in February 1922, when Downton Abbey is still in deep mourning for the loss of heir Matthew Crawley (Dan Stevens) from an auto accident.

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"Both the audience and the characters have experienced some passage of time," executive producer Gareth Neame said at PBS' Television Critics Association fall preview of Masterpiece on Tuesday. "We need to feel that something has happened since we were last there."

Neame was joined by a panel of Downton's ladies -- Michelle Dockery, Laura Carmichael, Joanne Froggatt, Phyllis Logan and Sophie McShera -- to present a sneak peek and answer questions about the upcoming fourth season, which won't premiere stateside until January.

How will the family cope? And what dramas can we expect upstairs and down? Read on!

UPSTAIRS

Lady Mary Crawley (Michelle Dockery) Without Matthew, Mary is at her flintiest, but we can't blame her since she really did lose the best part of herself in a "stupid car crash." But even the always loyal Carson (Jim Carter) has had enough of her attitude and observes that she's letting herself "be defeated." Out of the mouths of servants! Meanwhile there is at least one possible new man in her life, played by Tom Cullen. "He is an old family friend, and she's known him since she was tiny," Dockery said. "She's slowly coming back to real life. It's important for her to eventually move on, so he is a potential love interest." And, surprising to no one, Mary isn't the most maternal of mothers to poor little George. "It's hard to bond with the baby because she's going through the grief," she said. "And when she sees him, she sees Matthew."

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Lady Edith Crawley (Laura Carmichael) The oft-fooled and jilted Crawley sister will resume her journalistic pursuits and that tenuous relationship she had with her editor Mr. Gregson (Charles Edwards), who is more ardent than ever and even mentions marriage. "Yes, she is still involved with the paper," Carmichael said. "We haven't seen Gregson for some time due to the fact that the family is in mourning, but she's still turning in some articles. I like to think of her as a bit of a Carrie Bradshaw of the '20s. Edith goes to London a lot. " Neame added that "It really is a different story for Edith this year." It certainly looks like Edith is flourishing in the '20s. She's embraced the drop-waist flapper styles and appears more open and relaxed. She even gets to eat publicly in a restaurant! Also, expect her to have something to say about women getting the right to vote in America.

Lady Rose MacClare (Lily James) "We see the streets of London, and Lily James' character Rose is one of the Bright Young Things," Carmichael said. Through Rose, we'll see more of an escape from the dreary Downton mourning and more of that modern feel as the aristocracy fades.

Violet Crawley, Dowager Countess of Grantham (Maggie Smith) As usual, she's alive and kicking ass, verbally. In the preview trailer, the Dowager Countess is the one who thinks of a scheme to get Mary back on her feet (see below), despite Lord Grantham's (Hugh Bonneville) reluctance to push his daughter. Also, she'll be just as opinionated as ever, especially when it comes to the liberal politics of Prime Minister David Lloyd George. "Every time he's mentioned, Violet has a seizure," Neame said. "We really want audiences to connect with these people to feel they are as much like us."

Tom Branson (Allen Leech) Like Mary, Tom is dealing with the loss of a spouse and playing single parent to a young child. Perhaps those similarities are why Lady Violet was inspired for her latest scheme: Having Mary learn how to run an estate on behalf of her infant son George. "I want Tom to be your instructor," said the Dowager Countess in the preview. Don't expect anything but sympathy and business between the mournful in-laws though. "They are very much friends, and he is her brother-in-law still," Dockery said. "They've become close because of what they've been through, and because Mary becomes far more involved with the running of the estate. But romantically, I don't think it's going anywhere. I hope not!"

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Cousin Isobel Crawley (Penelope Wilton) From the preview, we see that she's struggling with the loss of her son Matthew, perhaps even harder than Mary is. Neame teased that in an upcoming scene, all the widows and widowers -- Mary, Tom and Isobel -- gather together to commiserate. "They all reflect on their great, deep loves," he said. "It's a beautiful scene. And in a line, they each share how deeply they loved their partners. And before it gets maudlin, Isobel says, 'Aren't we the lucky ones?'"

DOWNSTAIRS

Mr. Carson and Mrs. Hughes (Phyllis Logan)
Sorry, 'shippers! The leaders of Downton's staff are not going to follow in Bates and Anna's romantic footsteps anytime soon. "No, we still have a very nice working relationship. We have occasional spats here and there and ... drink a glass of sherry together of an evening," Logan said. In the sneak peek, we see Carson read a piece of mail, but then discard it in the trash, which Mrs. Hughes eyes with interest before the scene cuts. Could this reveal the snoopier side of the head housekeeper? "I think she's a bit of a busybody, really," said Logan. Neame added, "She and Carson are the Greek chorus of the show and comment on every story that is going on."

John and Anna Bates (Brendan Coyle, Joanne Froggatt) The lovebirds are going strong when we drop in on them, and they are flirting about Valentine's Day and secret admirers. We also see Lady Rose try to enlist Anna's help in a scheme to go to the village to engage in behavior that is more fitting for "servants and farm workers," as Anna puts it. "I think Anna is the beating heart of the show," Neame said. "She is the character I'd most like to have as a friend."

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Daisy Mason (Sophie McShera) and Ivy Stuart (Cara Theobold) The two kitchen staffers are still under the command of Mrs. Patmore (Lesley Nicol), but Daisy has a new air of confidence and competence about her now that she's the assistant cook. Meanwhile, Ivy's thoughts are still on going out and hanging out with the lads.

Thomas Barrow (Rob James-Collier) "It's a complex world for him going forward," Neame said. "I heard rumors that O'Brien (Siobhan Finneran) is heading for the hills," which shakes up his need for control. He will also continue his rivalry with Carson to usurp the power in the household downstairs.

OUTSIDERS

Martha and Harold Levinson (Shirley MacLaine, Paul Giamatti)
"[The Crawleys] have American relatives who visit every year or couple of years," Neame said. "Grandmother Martha comes back, and Cora's brother, played by Paul Giamatti. He's been in England for the past two [or] three weeks enjoying warm beer." Check out more info on Harold here.

An opera singer and a jazz musician (Dame Kiri Te Kanawa, Gary Carr) As was announced previously, Downton Abbey will be filled with music thanks to real-life opera singer Dame Kiri Te Kenawa, who plays an opera singer who visits the Crawleys' home "and sings for them all." Meanwhile, the series continues to modernize by investigating "a lot of [early jazz] performers who traveled to Europe" in Carr's character, Jack Ross. "I think he's got a great voice," Neame said.

Downton Abbey premieres its fourth season in America on Sunday, Jan. 5 on PBS' Masterpiece.