This article is sixth in a series. The author is following the trail of the Lewis and Clark expedition across the North American West. Along the way, he's reporting on 200th-anniversary events at pivotal locations, and on what happened all those years ago.

This September things suddenly got interesting for the reenactors who have been retracing the route of Lewis and Clark up the Missouri.

Until now their trip has been fairly routine: days on the river chugging upstream, stopping at the larger cities for ceremonies and interviews and lectures, at the smaller towns and villages to give the little talks that Scott Mandrell, playing the role of Meriwether Lewis, calls his "harangues," and entertaining visitors to the boats.

It's been hard at times. One night in July a woman drove up to where the boats were anchored to the riverbank at 3 a.m., trained her headlights on the boats, and refused to turn them off. The men often feel that they never have time to themselves, and they all miss their families.

But in general, people have been kind and generous and interested. Even the Indians. On August 3 they reenacted the Council Bluffs event, in which Lewis and Clark met with a group of Oto and Missouri chiefs, gave them peace medals, told them they now had new "fathers" who owned these territories, and asked them to live in peace with their neighbors.

Representatives of the Omaha tribe surviving in the area came to the Council Bluffs reenactment, and the ceremony went well.

On August 28, crossing Nebraska, the reenactors held a "mock council" with the Yankton Sioux, and there were more ceremonies the next day. Everyone seemed to get along famously. In mid-September all that changed. Mandrell began to hear rumors that the Lakota, a branch of the Sioux, were going to try to stop them. The rumors turned out to be true.

On September 19 a Lakota chief named Alex White Plume came to the reenactment camp site on the Missouri with some 25 followers carrying a banner that read "Why celebrate genocide?" and told them, "We're here to ask you to turn around and go home."

The reenactors were, he said, opening old wounds. He then warned the group that if they didn't turn around he would attack with "bows and arrows." Others said they would sink the ships, and still others talked about bodily assaults on the reenactors themselves.

It was a tense meeting, charged with emotion. Chuck Haga, a reporter for the Minneapolis Star Tribune, says that "some of these folks are veterans of Wounded Knee in 1973," the famous confrontation between the American Indian Movement and the FBI. "It's the younger ones," he added, "that could see this as their Wounded Knee."

One of the most interesting things about this confrontation is that it almost exactly mirrors what happened to Lewis and Clark. They, too, had a relatively quiet summer climbing the Missouri's swift current, moving slowly north. They, too, had successful meetings with Oto, Missouri, Omaha, and Yankton Sioux chiefs.

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SOURCES AND RELATED WEB SITES Discovering Lewis and Clark National Geographic Lewis and Clark Interactive Site Missouri Lewis and Clark Bicentennial Commission Lewis & Clark National Historic Trail (National Park Service)