A secret meeting of minds

English playwright Michael Frayn's Tony Award-winning play "Copenhagen" comes to the small screen on the wings of a stellar cast and an illuminating cinematic style that is worlds away from the frank theatricality of the original. Three actors on a stage, three chairs, no scenery.

The eminently worthy KCET Hollywood/BBC production (PBS, Sept. 29, 9-11 p.m.) may seem like a daunting subject for television (physicists, are you kidding?), but it works. It might be a good idea to turn off the phone before viewing, though – it does take concentration.

The story concerns an actual meeting between Danish physicist Niels Bohr and his protégé, German physicist Werner Heisenberg, both Nobel laureates and pioneers in atomic physics.

The two had been fast friends for 20 years. Then, as the Nazis came to power, Heisenberg chose to stay in Germany and work on atomic energy for them, which created a rift.

In 1941, the Nazis had not yet tried to transport Danish Jews to the concentration camps. (Danish citizens later rescued nearly all, more than 8,000, in a daring midnight escape.) Bohr, who had a Jewish parent, was, of course, a world-class scientist and therefore under the strictest observation by Nazi officials.

Heisenberg knew enough to draw his mentor out for a walk to evade Nazi bugs. It was on that walk that Bohr became angry with his old friend.

Why did Heisenberg visit Bohr at his home in Copenhagen in 1941 during the Nazi occupation? What did he want to talk about? Was he trying to find out how much Bohr knew about British and American progress on the bomb? Was he trying to pick Bohr's brain about scientific advances? Or, was he trying somehow to save Bohr?

Heisenberg left his benign version of the story – and Bohr left a much different account. The play posits several possibilities with such deft creativity that the real focus of the story gravitates away from science toward their very human relationship.

Mr. Frayn investigates that complex relationship from an original perspective. He has the ghosts of Bohr and his wife, Margrethe, meet the ghost of Heisenberg.

Once more, they return to 1941 and to the Bohrs' old home, discussing the meeting from the vantage of history – with the ironies of hindsight at their disposal. For example, Heisenberg may or may not have been working on the bomb, but it was the good and decent Bohr who helped perfect it in America.

And for those of us out there who quake at the idea of listening to physicists speak to each other, physics is not the point of the play. It's also comforting to realize that Frayn has no formal education in physics.

"I studied philosophy, and if you study philosophy you can't help but come across quantum mechanics, because it has so many extremely strange philosophical implications," Frayn says.

"It's been very much a layman's interest, but a powerful one," he adds. "But I was also always interested for philosophical reasons in why people do what they do."

The story of Heisenberg's visit to Bohr fascinated Frayn because it suggested a parallel between the uncertainty principle that Heisenberg introduced to physics (simplistically put: We can never know everything about a physical object and its behavior) and the uncertainty of knowing why people do what they do.

It was very difficult to know what Heisenberg's motives were – and impossible to settle the question, he says.

"The light that is cast on human behavior is the light that comes from an analogy with the physical sciences," says Frayn.

Though the play has been cut a bit, the film is a rich and compelling experience. Frayn says that Bohr was fluent in many languages, but spoke so softly people couldn't tell which one he was speaking in. Irish actor Stephen Rea captures that quietness – without becoming inarticulate.

Francesca Annis as Margrethe is the perfect helpmate. She and Rea create an absolutely believable intimacy that helps define Bohr's character as an honorable man. And English actor Daniel Craig keeps Heisenberg cold and hot at the same time – leaving us wondering again if he is better or worse than he seems.