"We want you to do it again." These words, spoken to fifteen-year-old Brian Robeson, will change his life. Two years earlier, Brian was stranded alone in the wilderness for 54 days with nothing but a small hatchet. Yet he survived. Now the government wants him to go back into the wilderness so that astronauts and the military can learn the survival techniques that kept Brian alive. Soon the project backfires, though, leaving Brian with a wounded partner and a long river to navigate. His only hope is to build a raft and try to transport the injured man a hundred miles downstream to a trading post — if the map he has is accurate.