The Worldloppet is a series of 10 cross-country ski races held every winter in Europe and North America. The shortest race is a 42-kilometer sprint through Switzerland. The longest is 89 kilometers across Sweden. The marathon series, which squeezes 642 kilometers of racing into just eight weeks, is to cross-country skiing what Hawaii's Ironman Triathlon is to a Sunday stroll.

So when Stuart Stevens, a 30-year-old Washington writer and political consultant with minimal nordic skiing experience, told Worldloppet officials he wanted to become the first person to compete in all 10 events in the same season, they didn't bother to argue with him.

"It is impossible, obviously," said Claudio Chiogna, the secretary of the organization.

Last week, Stevens was at the American Film Institute for the premiere of a film that proves the experts were wrong. Titled "Marathon Winter," the 55-minute film shows Stevens pursuing a Worldloppet schedule last winter that would give a travel agent motion sickness.

"If anything had gone wrong anyplace, it would have ended on the ground," said Jody Jaeger, the director of the movie. "The logistics looked a lot better on paper than they did after you crossed the Atlantic six or eight times."

Consider the weekend of Feb. 18-19. On Saturday, Stevens competed in a 55-kilometer race in Canada. Fifteen hours later, Stevens was in France, at the start of a 76-K race. The following weekend, he performed that jet lag two-step again. He completed a 55-K race in Wisconsin on Saturday, then raced to the airport for a flight to Finland and a 75-K race the next day.

"I was lucky. I didn't get sick at all. And that's one of the big things I was worried about," said Stevens, a solidly built, blue-eyed man who grew up in Mississippi, where cross-country skiing is not exactly an obsession.

Last year, when Stevens decided to attempt the Worldloppet circuit, he explained that his motivation was "a curious mixture: the sheer athletic challenge, the excitement of trying something that's never been done, the pressures of turning 30, and the total zaniness of it all." If it made sense to him, he had a harder time convincing some friends of its merits.

One friend summed it up this way: "You're spending a year of your life making a film about losing a lot of races no one's ever heard of?"

But if the Worldloppet is obscure on this side of the Atlantic, it is celebrated in Europe. Some races attract more than 13,000 competitors and spectators line the route, ringing cowbells and cheering racers who are international figures.

"They are the big sporting events of their country," said Stevens, who was adopted by the Swedish team and its coach, Kjell Kratz. "People sit out there along the course, dig holes in the snow and build fires. It's an incredible feeling."

The biggest and most prestigious event on the Worldloppet circuit is Sweden's Vasaloppet race, the longest of the series at 89 kilometers. It was during the Vasaloppet that Stevens fell, and nearly failed.

The Vasaloppet was held on the weekend after the two consecutive weekends of back-to-back races in North America and Europe. Having survived those twin ordeals, Stevens did not expect the Vasaloppet to be particularly taxing. But with 29 kilometers remaining in the race, the eighth of 10, Stuart hit the "wall" with a thud.

"All the previous races caught up to him," said Jaeger, one of seven people in Stevens' entourage. "He fell face down in the snow. He had cramps, was vomiting and bleeding from the nose. This little medical M*A*S*H unit grabbed him and threw him in the ambulance. They were trying to keep people from dying and giving the race a bad name. We had a heck of a time getting him back out on the course."

Stevens finished the Vasaloppet, as he did all 10 races. In the process, he became something of a celebrity in Europe.

"People surrounded him at races," cameraman Kendall Wilson said. "They were crazy to meet Stuart. They wanted to meet a walking dead man."

Stevens and his partners now are trying to sell the film to cable television. Meanwhile, Stevens is back in Washington, planning other adventures and feeling the confines of ordinary life after his extraordinary winter.

"I really loved being an athlete," he said. "It was fantastic the way my life all of a sudden got real simple."