Sam Morgan, once a young runaway from Philadelphia, now a seasoned fur trapper and mountain man, faces the most daunting task of his adventuresome life. It is 1827 and he, together with the trapping brigade commanded by Jedediah Smith, has been expelled from Mexican California. To his unending sorrow, Meadowlark, Sam's beloved Indian wife, has died in childbirth and he has been forced to abandon his infant daughter, Esperanza. Now, Sam is determined to reclaim his baby and take her to Meadowlark's village on the Wind River of Wyoming.