A 10-year-old child prodigy cartographer secretly leaves his family's ranch in Montana where he lives with his cowboy father and scientist mother and travels across the country on board a freight train to receive an award at the Smithsonian Institute.

Young Frenchwoman Mathilde searches for the truth about her missing fiancé, lost during World War I, and learns many unexpected things along the way. The love of her life is gone. But she refuses to believe he's gone forever — and she needs to know for sure.