Kenneth Branagh keeps leaping between extremes.

He goes from epic to intimate, from sprawling movies to tidy TV shows.

The movies he’s directed – including “Thor” and “Cinderella” – have been massive and colorful, with action and fantasy. His “Wallander” mystery movies on PBS are pretty much the opposite.

“Wallander” – returning for three Sundays – fits its setting. “The first things that struck us (were) how big it was,” Branagh said of rural Sweden, “how flat it was, how far away it seemed, how isolated.”

All of those are traits shared by Kurt Wallander, the police detective he plays.

The “Wallander” mysteries are filled with quiet understatement. Indeed, it’s tough to grasp the fact that Branagh was starring in one of them while he was planning his “Thor” movie.

Back then, Tom Hiddleston – like Branagh, a Shakespearean actor – was playing his “Wallander” assistant; Branagh had just cast him in “Thor” as Loki. He recalls Hiddleston’s “kind of very youthful, wide-eyed kind of innocent-looking expression as he thought, ‘Really? I’m going to be doing that? Really? We’re going to be in space, and we’ll be in the middle of all that kind of adventure?’”

And now? Hiddleston has gone on to be Loki in three more movies, with a fourth on the way; he doesn’t have time to do “Wallander”.

Branagh, however, does. He keeps returning to “Masterpiece” in different projects. “The series has had no better friend than Sir Ken,” said Rebecca Eaton, the “Masterpiece” producer.

This feels like familiar turf, Branagh said. “I grew up watching television, so it was very important.”

That was in Belfast until he was 9 and then in England. He became a hybrid – British accent, Irish soul, blue-collar roots (his dad was a carpenter who started a specialty company) and upscale education.

Branagh, now 55, did the classics and at 27 starred in the “Fortunes of War” miniseries, which would change his life. He fell in love with his co-star, Emma Thompson; they married, divorcing six years later. And he made his first trip to Los Angeles, to talk to reporters at a “Masterpiece” press conference.

The flight was six hours late and “people had been well-refreshed at that stage,” Branagh recalled, bringing a loose night of music and laughs. “The next day, I went for a walk in Beverly Hills .... You really felt the distance and you thought, ‘How amazing that this thing called ‘Masterpiece’ is gathering all these people together on the other side of the world to talk about ... our work.”

Branagh twice rejected offers to be the series host, Eaton wrote in “Making Masterpiece” (Viking, 2013). Still, she wrote: “Ken has remained a great and loyal friend to ‘Masterpiece’ and seems to understand better than most actors, what a ‘Masterpiece’ broadcast can do for a British actor’s career.”

TV has always seemed vital, he said. “My family weren’t theatergoers, but we did watch television. We went to the movies. And I was just aware ... of how influential was the shared conversation about art or entertainment you’d seen in your living room.”

So when he read the “Wallander” novels, it seemed logical to film them for “Masterpiece,” shooting in the Swedish locations they described. “It’s the land of the big sky, small houses, certain kinds of colors used,” Branagh said. “And everyone seemed to be in a rather melancholic painting.”

The project has included 12 TV movies, shot in four three-film batches, spread over seven years. Reflecting the novels, Wallander sometimes went abroad ... and, at the end, showed his age.

So this year’s first film finds Wallander in South Africa; the next two find his mind retreating, Branagh said. “His own particular isolation ... makes things pretty tricky, if he is starting to become forgetful.”

There’s no 'Thor'/'Cinderella' solution here. There’s a bright and lonely man, facing a premature fade.

WORTH WATCHING
•“Masterpiece: Wallander,” 9-10:30 p.m. Sundays on PBS
•Final season has three films, May 8, 15 and 22