Rufus Sewell may play a loyal lieutenant of Adolf Hitler in Amazon’s Man in the High Castle, but this isn’t your grandfather’s Nazi.

And Sewell knows it.

“I thought it would be interesting,” he says, “to see it from a different perspective.”

Man in the High Castle, the dark, intense sci-fi drama whose second 10-episode season has just been released on Amazon Prime streaming service, portrays America 15 years after Germany and the Axis forces won World War II.

Sewell’s character runs the German sector of conquered America, which stretches from the Eastern seaboard almost to the Rockies. His name is John Smith, the quintessential ordinary American name.

Smith is not your regular cold-blooded sneering Teuton. He’s an American who runs an office, a coolly efficient administrator who goes home to his family at night.

In many ways he comes across as an exceptionally successful bureaucrat who won enough of Hitler’s trust to earn a title that barely fits on a business card: obergruppenfuhrer.

In season two, Smith is rewarded with a mission personally dear to the aging and increasingly infirm Hitler. He must find The Man in the High Castle, a mysterious fellow who inspires the resistance movement by collecting and distributing newsreel films that seem to show an entirely different world in which the Allies, not the Axis, won the war.

That’s the sci-fi side of Man in the High Castle, which is based on the 1963 novel of the same name by Philip K. Dick. But the novel, and now the TV adaptation, focus more on the chess matches among the characters, many of them ordinary people who must choose a side and accept the sacrifices necessary to support it.  

This makes many of the characters multi-dimensional, and Sewell acknowledges the challenge this presents with Smith.

“You’re exploring a conflict,” Sewell says. “If you want to humanize a Nazi, it’s important to remember that it’s humans who are capable of the things that the Nazis do.

Among other things, he says, this entails showing how ordinary people “could have been drawn into this world, how you could become a full believer in the Nazi ideology.

“You must become adept at not seeing things that wouldn’t support that belief.”

He points to the real-life Albert Speer, the architect who became the real-life Hitler’s minister of armaments and war production.

“Many of the things Speer built relied on slave labor,” notes Sewell. “After the war, he said he was not aware of this. He said he didn’t go to Auschwitz, that the place was never mentioned.

“I think he meant he never looked in that direction. But you can become complicit by what you choose to look away from.”

That’s the kind of moral question Sewell says he weighs in portraying John Smith, who rejected his own country’s traditional beliefs to embrace this extreme German ideology.

“My job,” Sewell says, “is to think, ‘Who is this guy?’ When the writing sounded a Nazi-esque, I’d push for it to sound more American.”

Smith is smart and smooth, the kind of employee who could rise in any organization. “He could be anything,” says Sewell. “It’s interesting to see him engaging at a social event, in a different setting, with different relationships.”

Still, Smith remains the obergruppenfuhrer, a position that requires a chilling ruthlessness. and Sewell admits this can be “haunting.”

But at 49, Sewell has been an actor for a long time, playing everyone from MacBeth to Alexander Hamilton to a feral cat, and no, he says, he didn’t take John Smith home with him.

In fact, he spent a good part of this year playing Prime Minister Lord Melbourne in the public television series Victoria. Victoria played in the U.K. this fall and comes to PBS in the U.S. on Jan. 15.

“They’re quite different,” Sewell says with a laugh. “Melbourne is much more like me.

“But I feel equally at home playing either. This is the work I want to do. If you want to act and you’re offered the part of an interesting villain, you take it, just as you take an interesting hero. So it’s easy to go from Lord Melbourne to a Nazi.

”With any character, you always want to go deeper. In season two of Man in the High Castle, we do.

“I think that’s important, and necessary. It’s comforting to dehumanize the Nazis, but in the end, all that does is let us off the hook.”