Christina, Grant, Mimi, and Papa go "all aboard" the train Papa's borrowed for a fast adventure across America. They try to keep from being "derailed" by mysterious mishaps, spooky surprises, and - oh, it's so dark in here! - those treacherous tunnels! 

Look What's Inside This Mystery - people, places, history, and more! 
Places: Washington, D.C. - Union Station • The National Mall • Washington Monument • Lincoln Memorial; Nebraska - Union Station • Union Pacific Railroad Historical Museum • Chimney Rock; Missouri - Museum of Westward Expansion • Independence • Eads Bridge, St. Louis; Colorado - Union Station; Utah - Salt Lake City • Promontory Summit; and Mississippi River and Sierra Nevada Mountains