'Downton Abbey' Ends Tonight

— -- It's already aired across the pond, but the series finale of "Downton Abbey" will air in the U.S. tonight on PBS.

Will Lady Mary and Lady Edith bury the hatchet? Will Lady Edith finally get married? Will Thomas get a new job? Will Mrs. Hughes and Mr. Carson stay together? Will Anna actually have a baby?

These are all questions fans are hoping to get the answers to -- but will they, and will they like those answers? We talked to some experts to find out.

"It's always been a really feel good show, even though some horrible things do happen," Entertainment Weekly correspondent Kevin P. Sullivan told ABC News. "In terms of finales, people are just looking for happy endings for the characters that they've really come to enjoy over the last six years, and I think everyone just wants to see Edith finally have a happy ending and finally settle down and not be so tragic for once."

Sullivan, who has seen the series finale, said that it's Lady Mary who is going to have to go through the biggest change, since the last time we saw her she deliberately ruined her sister Edith's chance for a happy marriage.

"I think people need to be watching Mary," he hinted. "She really kind of sank to her lowest in the last episode. We see her do something absolutely unforgivable, and where do you go from that? I mean, we have to end the show ... they have to put a final note on Lady Mary, and if that's where the second-to-last episode leaves her, you can imagine there's quite a road for her to travel to end up at a place that is forgivable."

Sullivan added the finale had "a lot of great closure" and expected it to be well received.

"It certainly won't be controversial," he said. "I think fans will mostly just be sad that the show's over and they won't have anymore 'Downton' to watch."

Jessica Fellowes, the niece of series creator Julian Fellowes and the author of "Downton Abbey: A Celebration," the show's official guide, told ABC News fans will enjoy the finale because her uncle designed it that way.

"I asked Julian if he always had in mind where he wanted the characters to end up and he said 'Yes,'" she said. "And I said, 'And did you get them there?' and he said, 'Yes, I did!' So I think it's the ending that he wanted."

"I'm not saying that he's necessarily wrapped things up exactly as everybody is expecting or wanting," she clarified. "He's good at throwing us a curve ball, but I thought it was an immensely satisfying ending."

So does that mean Lady Edith is going to get her happy ending?

"I think really it just depends on what your definition of a happy ending is," Fellowes said. "For many people, it was about Edith getting married and for others, it's about her being this very interesting pioneering woman in London, so it depends on where you're coming at it from."

The show has been so popular in the U.S. for the past six seasons because it plays into our fascination with the British class system -- but there's more to its appeal than that, experts said.

"I think one of the reasons people have clung to the show so much is because of how essentially good these characters are, even though they do make mistakes sometimes," Sullivan said. "Especially in an era when TV is really kind of leaning on the antihero, and the shows that do get great praise, like 'Mad Men' or 'Breaking Bad,' are essentially about people who are corrupted and I think 'Downton Abbey' was kind of a counter-note to that."

"I think essentially it's about family, whether it's the working family or the blood-related family, and I think those dynamics are ones that we recognize," added Fellowes.

Even though "Downton Abbey" the TV show is ending, this may not be the last we see of the Crawley family. Fellowes said her uncle would like to do a "Downton" movie at some point, so "we should keep our fingers crossed."

"Nothing's going to stop him," she said of her uncle, laughing. "There's going to be plenty of things to plug the gap, I think."