Laura and her family are moving west again, this time to the Dakota Territory. Laura really likes their frontier home until the night she and Carrie take a walk and come face to face with a huge prairie wolf!

Forced to leave New York City to move in with her aunt in South Dakota, once-wealthy orphan June comes across her mother's coin collection and determines to find a rare penny worth one million dollars so she can return to her life of privilege.

Hoping to escape the attention brought on by the accident that flattened Stanley, the Lambchop family drives to South Dakota, where they become involved in a wild west adventure at Mount Rushmore.