The series will end at the start of World War IIWith the house taken over by the government for the duration (and perhaps decades longer), and a Distant Finale showing it presently under National Trust administration with the Crawley descendants scattered throughout the world.
Mary and Tom will be each other's Second LoveHe's just lost his wife, she's just lost her husband. Both their children are close enough in age to be brought up together. With Matthew's death, the next heir to Downton becomes his newborn son, so Robert doesn't have to go shaking the family tree for any distant cousins to marry his daughter to preserve the Grantham line. Plus, the Christmas Special made much of the fact that both Tom and Mary don't really have people who truly understand them, save for their significant others. They can bond over their perceived distance from the rest of the family, their grief, their children. Whether it will end with them being happy together permanently is a different story, but them hooking up initially? That's going to happen.
Mary will find somebody in AmericaLet's face it, the whole idea of Mary going to America to "find a cowboy in the Middle West to shake [them] up a bit," as Robert put it, was a case of They Wasted a Perfectly Good Plot - even if that aspect was ignored over the joy of seeing Mary and Matthew FINALLY get together. Now that Matthew is dead, the family may decide to have Mary go to America anyway to grieve in peace, and to find someone else. It certainly makes a lot more sense than traditional, haughty Mary hooking up with rebellious, common-born Tom, much as they may make sense in other respects.
Branson and Rose will get togetherWith Rose moving to Downton next series, all the Sybil-Rose parallels and hints of Tom possibly finding someone to help him cope with his loss, it's not unlikely that this will happen. While Rose is a lot less mature than Sybil ever was, we'll probably see her shed her naivety and whatnot next series.
Daisy Robinson is an ancestor of Daisy Wick of 'Bones'Not only does Sophie Mc Shera bear a striking resemblence to Carla Gallo, the two characters seem to share a lot of the same [[Genki Girl]] personality traits, although they are much more repressed in the humble, "simple minded girl" role of subserviant Daisy Robinson.
The show is about Mary and her growth into maturityThink about it. When the show starts Mary is a spoiled and self-centered brat but over the 3 seasons she grew more and more mature. And now, with the death of Matthew she will have to grow more mature to handle the changing world.
Mary is a succubusPamuk tried having sex with Mary, he ultimately died. Lavinia, when she fell ill, was brought to rest on Mary's bed. She died. Matthew slept with Mary in the same bed. He died as well. Clearly... Mary is a succubus or some sort of demon.
Somewhere in the shows time skips a few episodes of Jeeves and Wooster occured.Both TV shows match each other to the year and if the Earl and his money mismanagement let to the temporary loss of Downton sometime after WWI (Which no one in the Crawley family speaks of out of shame) to the Basset family who had the place renamed to Totleigh Towers then we have a perfectly reasonable explanation for why Bertie Wooster is seen puttering about Downton Abbey.
The series will at least reach 1925Why? Because that's when the Law of Property Act 1925 was passed, abolishing entail entirely.note This will be a moment for fantastically awkward (and very Downton) humour as everyone looks at the perfectly-healthy Robert and remembers how they had been in a tizzy for eight years about something that, as it turned out, was completely irrelevant.
Thomas will finally get some in s4.Because God knows the poor man's been disappointed so many times over the course of the entire show.
Rose will have a relationship/fling with Gary.Rose likes Jazz music and is a modern flapper, so its easy to see her hooking up with the (Black) Gary. One of the pictures for season 4 shows them rowing a boat together.
There will be some other heir ahead of Mary's son.Matthew may have been the next heir, but he died before the title and property passed to him. If there is another adult male heir who was just as close a relation to the Earl as Matthew was, but a little bit younger or otherwise put behind him in the succession, they may still be ahead of the one-generation-further-removed baby. Of course, once entails are outlawed in 1925, Mary will be declared the heir instead, but they won't be able to resist milking the succession issues one more time for everyone who hasn't looked up entails....