April 7, 1805. The worst winter you have ever known has ended, and thanks to the Mandan Indians, whom you have stayed with here at Fort Mandan for the past few months, you and your Corps of Discovery have survived unharmed. Now, it is time for the expedition to get underway again. Including yourself and Captain William Clark, the other leader of your group, only thirty-three of the original forty-odd members of the Corps remain. Among those remaining are York, Clark’s black slave; Sacagawea, a Shoshone Indian woman; Toussaint Charbonneau, a guide, interpreter, and Sacagawea’s husband; Pomp, Sacagawea’s infant son; and Seaman, your Newfoundland dog.

It has been over a year since President Thomas Jefferson named you to lead an exploration of the newly-purchased Lousiana Territory. Jefferson hoped for two things: that you would document the vast, unexplored area between the Mississippi River and the Rocky Mountains, and that you would find the Northwest Passage, an easy water route that linked the Pacific and Atlantic Oceans and opened trade with the Orient. So far, your journey has been successful. You have discovered numerous new plant and animal species. In fact, you’ve just sent a boat full of reports and scientific specimens – including a prairie dog – back to the East and to Jefferson.

But you have yet to locate the Northwest Passage. You assume that it lies somewhere in the miles ahead, but you have no idea how many miles away that is. After all, the maps you have only go as far west as you are now. You’re about to lead the expedition off the map, into the unknown.

With six dugout canoes and two pirogues (larger canoes) fully loaded with supplies, you and your men bid the Mandans farewell, and start paddling up the Missouri.