LOS ANGELES — When Michelle Dockery looks back at the first episodes of “Downton Abbey,” she marvels at how young everyone looks.

“We’ve grown up together,” the Emmy nominee says. “As an actor, you’re constantly worried where the next job is coming from. But this gives us all a slight sense of security.” And how.

If creator Julian Fellowes had a way of writing episodes that bring “Downton” into the 21st century, they’d probably get made. The British series has such a rabid following that U.S. fans seek ways to see the episodes when they’re run months earlier in Britain.

The fourth season — now ending in Europe — begins at 8 p.m. tonight on PBS. Some time has passed since the car accident, and Dockery’s Lady Mary is trying to carry on without her husband.

Does love find Lady Mary? “She actually has more than one love interest,” Dockery says. “She’s kind of slowly coming back to real life. It’s important for her to eventually move on.”

When Dan Stevens — who played the ill-fated Matthew — told producers he wanted off the show, they had to figure out a way to handle the loss in the story. Death? Breakup? War?

“Initially, I was concerned what would happen,” Dockery says. “But as much as it was sad to see Dan go ... it opened up opportunity for (Fellowes) to write a new chapter and something quite different for Mary and the other characters.”

This year’s new suitors, says producer Gareth Neame, are a bit like praying mantises: “They come up and they get to do it once, and that’s it.”

Baby George figures into the story, too, but Mary doesn’t bond with him much. “She looks at him and she sees Matthew,” Dockery says. 

Unlike Stevens, Dockery says she has no intention of leaving. “What’s wonderful about the show is that it has opened doors for all of us. If other actors start leaving, I think that would be a worry. But so long as it remains as an ensemble, we’re fine. We can do other things in between.”

And besides, co-star Joanne Froggatt says, Fellowes “writes really well for women. Maggie Smith (who plays the dowager) is kind of his muse in a way.”

In the fourth season, most of the leading actresses get pretty substantial story lines. 

“I always think this show is really good for women,” says Laura Carmichael, who plays Lady Edith. Even though she’s often in her sister’s shadow, this season she gets to ply her writing skills. Journalist, she says, “is a natural progression. It’s a natural thing for her to express herself and report. She’s a watcher and a loner.”

Downstairs, there’s much more action.

Sophie McShera, who plays Daisy, says there’s plenty of romance going on, “but nobody will give Daisy a break. She fancies Alfred, but he’s having none of it.”

Fellowes’ scripts, she says, often provide clues to what will happen. “The script is pretty self-evident,” McShera says. “It all makes sense in the end.”

And, like Dockery, she’s a “Downton” vet who has no desire to leave the series. “Downton,” in fact, helped her land a role in Kenneth Branagh’s live-action version of “Cinderella.” The title character?

“Even better,” she says. “I’m a wicked stepsister.”

Because upstairs and downstairs scenes are shot on different sets, not all the “Downtown” cast members have an opportunity to mingle. When they get together, it’s like a reunion.

Dockery spends the most time with Maggie Smith. “She’s very funny, much like her character,” she says. “She always comes up with these zingers.”

Career advice? “With Maggie, it’s a lesson just watching her work.”

Knowing that they’ll all be employed next year, Dockery says, “is the best bonus of them all.”