Megan, twelve, and Zane, nine, want to go to Yellowstone National Park with their grandpa and grandma. When their parents say no, they take matters into their own hands, hiding in the back of the truck and going anyway. They never could have guessed they would end up having a magical, sometimes terrifying, adventure. Along the way, they meet a lost-in-time Lakota tribe and a very interesting mountain man, who help them along their journey. But the story is just getting started and becomes much more than a journey and an adventure.