It is the early 1860s and twelve-year-old Erik Larson and his Swedish family are headed west in a wagon train from Minnesota to find a valley in pre-Idaho Territory. The family holds high hopes that their new home will provide the happiness they seek-that is, until a deadly illness strikes. When Erik's own mother becomes ill, the wagon master decides to push ahead, intent on outracing a blizzard. Unfortunately, winter arrives with a vengeance, and with his sister far ahead in another wagon, Erik is stranded with his parents. After his father experiences a fatal fall, Erik and his mother face a brutal winter-alone on the windswept prairie. Erik is convinced that to survive he must seek help from the Sheepeater Indians. After he meets the Sheepeaters, he deals with prejudice and life-threatening danger and begins to question everything he's ever believed.
Without the skills to hunt or fish, Erik must confront an agonizing choice-either perish or abandon everything and become a member of the Sheepeaters. A poignant partnership soon unfolds between the Native Americans and a white man who has just one dream-to reunite with his sister.