Many have written of the historic expedition led by Meriwether Lewis and William Clark across the wilderness of the North American continent, but Cleary's fascinating account is told in the voice of John Collins, a friend of Georges Drouillard, a hunter contracted to supply the travelers with meat along the way. Collins finds it a challenge to make friends among the highly mixed company, including a rowdy bunch of French Canadians who are quite experienced in the ways of river travel. Eventually, his irrevocable oath of allegiance to the expedition creates a seemingly insoluble dilemma for the reluctant Collins, who now must make an impossible choice.