At long last, the astounding story of Raoul Wallenberg, the lost hero of the Holocaust, has reached the vast American television audience.

Tonight, the hour-long story will be presented on Channel 26 at 10. Titled "Missing Hero," the film is a model of documentary technique, intercutting real pictures from the past with present-day interviews in Israel, in Sweden, in Canada, in England.

The black and white newsreels and stills -- some of them taken by Wallenberg himself -- are perhaps familiar to us now. But they still yank us out of our daily lives and haunt us -- those faces, those people clambering onto trains to nowhere. Rarely has one hour on TV or anywhere else evoked the mighty range of the human spirit, the appalling and the sublime.

In a few days a new Congressman, Rep. Thomas Lantos (D-Calif.), will pay off a 36-year-old debt in his first congressional act. Lantos will introduce a bill making Wallenberg, the long-missing Swedish diplomat, an honorary American citizen.

Lantos was one of more than 100,000 Hungarian Jews saved by Wallenberg in the bitter closing months of the war in Budapest, when Adolf Eichmann and squads of Hungarian Nazis were doing their best to kill off all the Jews left in Hungary.

Wallenberg, scion of a great Swedish banking family, could have spent the war in safety and comfort. Instead, he rushed into Hungary with what American money he could get, printed up thousands of Swedish passports of his own design, and began literally pulling Jews off the cattle trains bound for Auschwitz, claiming them as Swedish citizens.

He bought or rented scores of houses in Budapest, equipped them with Swedish flags and called them Swedish territory. Day after day, he defended them with his physical presence when Nazis tried to break in or blow up the houses. Time after time, he faced the death squads with sheer force of will.

Rep. Lantos was 16 when he escaped to Budapest from a Hungarian labor camp.With an uncle and aunt (his parents had been taken away already) he was brought to a Wallenberg safe house in October 1944, to remain unharmed until the war ended in that part of the world.

He emphasizes that Wallenberg's heroism was not simply in buying up the houses but in physically defending them and in actually going to the railroad station to drag Jews out of the hands of their captors.

"When we see a child drowning, we're all heroes," said Lantos. "The thing about Wallenberg is that he sought out danger and probable death. He volunteered. He went in there and did something about what was happening to the Jews."

After the Russians took Pest, the east side of the city, in January 1945, Wallenberg was summoned to the Soviet headquarters on the 17th. He told aides he didn't know whether he was a guest or a prisoner. He never returned. a

The Soviets didn't even admit Wallenberg's existence until 1957, when hundreds of Germans returning from Russian prison camps confirmed they had seen him. The Russians then said Wallenberg had died 10 years earlier of a heart attack.

Reports kept drifting over the iron curtain. A Briton talked to a Swedish prisoner in Lubyanka in 1963, when no Swedes were known to have been incarcerated in the Moscow prison. Another man who said he met Wallenberg in '75 wrote to his daughter about it when he was released in '77, and was promptly re-arrested.

Meanwhile, the governments of the world belatedly began pressing the Soviets for word of Wallenberg. The Swedes, whose earlier requests for information had been timid, now began to speak more loudly. Simon Wiesenthal, the famous nemesis of Nazi criminals, learned of more sightings of Wallenberg. Just in the past few months, committees have been springing up around the word and rallies have been held demanding news of Wallenberg.And on Jan. 15, an international seminar honoring the man will be held at Stockholm.

How Lantos' bill will affect the search for Wallenberg can only be guessed. But surely, in combination with the TV documentary tonight, American pressure will increase. Attempts to have the Protestant Wallenberg proclaimed a saint have been to no avail. A more viable possibility is giving him the Nobel Peace Prize in hopes of forcing the Soviets to bring him out.

Wiesenthal says he thinks the Russians can only benefit in the world's eyes by producing the lost hero, now nearly 69 years old, even if they say it was all a mistake.

"It is our duty as people, not only as Jews, to help this man," he says.