T.S. Spivet (Kyle Catlett) is a 10-year-old prodigy with a passion for cartography and scientific inventions. He lives on a ranch in Montana with his mother (Helena Bonham Carter) who is obsessed with the morphology of beetles; his father (Callum Keith Rennie), a cowboy born a hundred years too late; and his 14-year-old sister (Niamh Wilson) who dreams of becoming Miss America. His twin brother Layton (Jakob Davies) died in an accident involving a firearm in the family's barn, which no one ever speaks of. T.S. was with him, measuring the scale of the gunshots for an experiment, and he doesn't understand what happened. One day, T.S. receives an unexpected call from the Smithsonian Institution, telling him that he is the winner of the very prestigious Baird prize for his invention of a perpetual motion machine and that he is invited to a reception in his honor where he is expected to give a speech. Without telling anyone, he sets out on a freight train across the United States to reach Washington, D.C.