LOS ANGELES – Directors, Jason Isaacs says, are surprised when they discover how he approaches playing the captain of a “Star Trek” starship.

“I don’t sit in the chair,” the British-born actor says. “I stay out of it. I walk up to the screen as much as I can and I conduct war like it’s an orchestra.”

A rare moment: Jason Isaacs is in his seat as the captain of "Star Trek: Discovery." CBS

Previously, “most of the exciting bridge scenes consisted of five people standing still at their station. I run around the deck” and the directors, he says, are delighted.

In the new edition, “Star Trek: Discovery,” he’s Captain Gabriel Lorca, a man in the midst of war just prior to the original “Star Trek” series.

“It is entirely the outcome role of the show to arrive at the principles ... that are endemic to ‘Star Trek’ and, at the same time not to suggest that doing that is simple or easy,” says Executive Producer Akiva Goldsman.

That means Isaacs’ character struggles with the situations he faces. “Our complicated story reflects some of the complicated decisions you make when you’re asking yourself, ‘Do ends justify the means or the other way around?’” Isaacs says.

When Isaacs, a star of the “Harry Potter” franchise, was pitched the new series, he had several long conversations with producers to make sure it was something he wanted to do for a long period of time. “It’s enormously good fun to dress up in Lycra and fire phasers,” he says. “But you want to know it’s something you can act. I don’t know how to play a starship captain. But they walked me through some of the complicated, difficult things he does.”

They also detailed Lorca’s past and “some of the secrets he’s got and the things that haunt him.” Special effects and green screen shots are just a bonus. “It’s an acting job like any other – if you don’t have secrets to play, you have nothing to do on camera.”

Michelle Yeoh, left, as Captain Philippa Georgiou and Sonequa Martin-Green, as First Officer Michael Burnham, discuss the escalating war in "Star Trek: Discovery." CBS

In the new series (which airs Sunday on CBS, then switches to CBS All Access for the rest of its season) the focus is on a first officer (played by Sonequa Martin-Green) who transfers from the USS Shenzhou to the Discovery. How – and why – that happens is part of the new series’ mystery. “Star Trek: Discovery” is also serialized, telling one story over the course of the season. Martin-Green’s character, Michael Burnham, was raised on Vulcan by Sarek, Spock’s father, which provides a link to the original series.

Mary Chieffo plays L'Rell, a Klingon, in "Star Trek: Discovery." CBS

How she interacts with Lorca is part of the discovery process. “We are complicated characters for complicated times,” Isaacs says.

When the 54-year-old actor learned Martin-Green’s character would be the show’s lead, he was thrilled. Since his daughters were born, “I’ve been searching for things that I could show them that I didn’t have to be embarrassed by and explain them away.” A strong female role model is important: “Her actions and ideas aren’t dictated by her relationships with men.”

Because it has the opportunity to comment on society, the new “Star Trek” will address a host of issues emerging in these “troubling, dark times,” Isaac says. “There’s no question we are part of a story that shows not just how it can all be harmonious in a big Diet Coke effort, but how you get there.”

From left, Sonequa Martin-Green, Mary Chieffo and Jason Isaacs talk about "Star Trek: Discovery." CBS

While Isaacs (who made a big impact on audiences in Mel Gibson’s “The Patriot”) was thrilled to watch the original “Star Trek” when he was a boy, he never considered “I would get to stand, one day, and say, ‘Energize’ and point phasers and run exactly the same way they did. It’s unimaginable that we are doing it and that we get paid for messing around like children in the backyard.”

Fate, however, brought him to this point, enabling him to play a leader who’s “sometimes bullying, sometimes encouraging.”

In the real world, Isaacs says, “leaders are having a tough time leading their people. I have a tough time in this, too.”

Drama thrives when people are placed in difficult situations. "Nobody buys a ticket to watch the village of the happy people."