Fryazino: The elderly former Soviet military officer who answers the door is known in the West as "The man who saved the world."

A movie with that title, which hits theaters in the United States on Friday, tells the harrowing story of Sept. 26, 1983, when Stanislav Petrov made a decision credited by many with averting a nuclear war.

An alarm had gone off that night, signaling the launch of U.S. intercontinental ballistic missiles, and it was up to the 44-year-old lieutenant colonel to determine, and quickly, whether the attack on the Soviet Union was real.

"I realized that I had to make some kind of decision, and I was only 50/50," Petrov told The Associated Press.

Despite the data coming in from the Soviet Union's early-warning satellites over the United States, Petrov decided to consider it a false alarm. Had he done otherwise, the Soviet leadership could have responded by ordering a retaliatory nuclear strike on the United States.

What made this even more dangerous was that the Soviet Union appears genuinely to have feared a surprise U.S. nuclear attack during what was an exceptionally tense period of the Cold War . That month, the Soviets had shot down a passenger plane flying to South Korea from the U.S., suspecting it of spying. The United States, after a series of provocative military maneuvers, was preparing for a major NATO exercise, called Able Archer, which simulated preparations for a nuclear attack .

In the movie, "The Man Who Saved the World," by Danish director Peter Anthony, actors portray the events of that night in 1983. The dramatic scenes are interwoven with footage of the real Petrov as an older man at his home in Russia, and on a 2006 trip to the United States, where he receives an award at the United Nations and meets with movie stars, including Kevin Costner, Matt Damon and Robert De Niro.

In his homeland, Petrov's role in history has won him little fame. He still lives in Fryazino, a town on the outskirts of Moscow, in a simple, unkempt apartment that looks much as it does in the movie, down to the long strip of yellow fly paper hanging from the ceiling. Unlike in the movie, where Petrov is shown angrily chasing out foreign journalists who have come to hear his story, he proves a gracious host, welcoming guests into his kitchen.