As Hitler's high-ranking functionaries, both military and civilian, met in a villa outside Berlin to discuss the fate of the Jews under their authority, a star was rising: Gen. Reinhard Heydrich, an ambitious man who one day might have headed the Third Reich.

On Jan. 20, 1942, Heydrich, deputy to Heinrich Himmler, and Col. Adolf Eichmann, head of the SS Jewish Affairs Office, met with 15 officials -- seven high-ranking officers of the feared SS elite and eight state secretaries of government ministries -- to discuss implementing a plan that would be new to some of them.

HBO's "Conspiracy," a dramatization of that conference, airs Saturday at 9 p.m. and runs just under two hours, about the same length as the meeting at Wannsee. The opulent villa -- previously owned by a Jew, according to the film -- was a place that Heydrich hoped to claim for himself.

Kenneth Branagh plays Heydrich and Stanley Tucci is Eichmann. David Threlfall, Colin Firth, Jonathan Coy and Barnaby Kay co-star in the production, which was written by Lorin Mandel, directed by Frank Pierson and filmed in London and at Wannsee.

"People said that [Heydrich] would be extremely charming, but he had this strange combination of characteristics," said Branagh. "He was a very fine musician and a terrific fencer, a sort of sophisticated, suave, urbane Nazi creature, tall and blond. He combined the kinds of things that were Hitler's model."

On that day, Heydrich set about reviewing with the group a problem that beset the Third Reich and possible solutions. As the German army rolled over country after country during World War II, the Nazis were becoming responsible for more and more people, millions of them Jews. The sheer numbers were becoming overwhelming, making difficult the Nazis' goal to expel Jews from the living space -- and indeed from every sphere of life -- of the German people.

Jewish ghettoes were full. As other countries grew reluctant to take more of Germany's castoffs, deportation was becoming less of an option. Sterilization would prevent those numbers from growing, but it wouldn't solve the Nazis' problem -- more than 11 million Jews, including 5 million from Russia.

As the Nazis saw it, even firing-squad executions were proving unsatisfactory. Ordering soldiers to line up Jews and shoot them so they fell into mass graves that they themselves had dug was adversely affecting troop morale.

As it turned out, Hitler's more efficient "final solution" was already under way.

In the film, after initial cordial greetings punctuated by the dramatic arrival of Heydrich, the officials gather around an oval table to discuss how to go about the ethnic cleansing of Germany. The meeting, which includes drinks and a buffet lunch -- sumptuous fare during war time -- is by turns good-natured (the officials rap on the table to show approval), pedantic, forceful and even bullying as Heydrich puts on a show of eliciting the participants' insights, concerns and suggestions.

"He seemed to have most things in his armory as far as arts of persuasion was concerned, but when charm didn't work, he was ruthless," said Branagh. "His force of personality, to some extent, rode roughshod over the others. Accounts from participants said that it was rougher and more brutal than the written protocol might suggest."

But Heydrich, to whom the Jews are simply "a storage problem," eventually lets the officials in on the new plan: mass deaths by extermination camps with poison-gas facilities disguised as showers, after which the bodies would be burned in ovens. Construction had begun two months earlier at Belzec and Chelmno in Poland. Heydrich was commandant of SS and police in the Lublin district of Poland.

Only Friedrich Kritzinger, ministerial director of the Reich Chancellery, appears to be significantly uncomfortable with the discussion. Still, when Heydrich tallies the group, Kritzinger says he won't oppose the plan.

There is some playing with words, "a certain caution about written material," said Branagh.

In the film, Rudolf Lange, who supervised the killing of 30,000 Jews at Riga, explains that "evacuation" is a euphemism for "extermination." "Sterilization" is "social re-engineering." There is much talk about "degrees of "mixed blood," what to do about Jews married to non-Jewish Germans and the administrative work to be sorted out.

Erich Neumann, who is in charge of the Reich's Four-Year Plan, is concerned about retaining enough workers in industries vital to the war effort, but he is the sort of man whom others tend to dismiss. Anyway, they tell him, most Jews don't know how to do manual labor and are a drain on the economy.

Interior State Secretary Wilhelm Stuckart wants to make certain that the law will support their decisions. Stuckart had attended the 1935 conference that enacted the Nuremberg Laws (and was a co-author) proclaiming the legality of a Jewish-free society and economy. A show of hands reveals that, like Stuckart, many of the participants are lawyers.

As he bids the participants goodbye, Eichmann promises to provide edited transcripts and asks each man to read and then destroy his copy. But Undersecretary of State Martin Luther, of the Foreign Office, apparently kept his. In 1943, Americans reviewing German Foreign Office papers found the 16th copy of 30 -- stamped "Top Secret" -- of the Wannsee Protocol, which refers to the gathering as a meeting about "the final solution of the Jewish question without regard to geographic borders."

As it happened, Eichmann remained influential in the Third Reich, but Heydrich died only four months later, in late May 1942, of wounds he suffered in Prague when Czech patriots tried to assassinate him.

"His bravado, his arrogance of manner led him to drive in an open-topped car in Czechoslovakia -- his aides asked him not to -- and he did not vary his routes to work," said Branagh. "This was part of his contempt, that no one would have the stomach to kill him. There are conspiracy theorists who say there may have been foul play involved in what may have been wounds he might have recovered from.

"There was concern that he could have been the successor to Hitler. He was a man whose ambitions might not be easily assuaged. He did so much of the Nazi dirty work -- he was a prime organizer behind Krystallnacht. He seemed to be a man without friends, had dirt on everyone, and was in a position to blackmail everyone. One of his techniques was to create bogus sexual scandals. He was efficient at collecting information . . . if there was anything unsavory."

The evacuation of millions of Jews to camps at Treblinka, Belzec and Sobibor was named Operation Reinhard to honor Heydrich.

Before the war, Adolf Eichmann had worked with Zionists to help as many Jews as possible emigrate to Palestine, which was under the control of the British. In 1944, skirting British law, he sent to Palestine his final evacuees, 1,000 Hungarian Jews.

After the war, Eichmann worked in Germany under a false name, then fled to Italy and later Argentina. In 1962, the Israeli Intelligence Service kidnapped him there and took him to Jerusalem, where he was tried and then executed.

At his trial, he testified of the Wannsee conference: ". . . the gentlemen convened their session, and then in very plain terms -- not in the language that I had to use in the minutes, but in absolutely blunt terms, they addressed the issue, with no mincing of words. . . . . The language was anything but in conformity with the legal protocol of clause and paragraph. . . . The discussion covered killing, elimination and annihilation."

The Wannsee villa is now a Holocaust museum, memorial and conference site. It opened in 1992 on the 50th anniversary of the secret Nazi conference.

"We shot the exterior sequences there," said Branagh. "I'm glad we didn't do the interior scenes there. It was chilling enough to be around the real place. It does create a very strong atmosphere of place. Just to stand in the room where it happened gave one shivers. At all times you had to shake yourself to remember that what we were doing was not a fiction."