T.S. Spivet is a 10-year-old prodigy with a passion for maps and scientific inventions. He lives on a ranch in Montana with his mother who is obsessed with the study of beetles. His father is a cowboy born a hundred years too late. His 14-year-old sister, Gracie dreams of becoming Miss America. His twin brother Layton loves the life on the ranch and likes guns, too. Unfortunately, he dies in an accident involving a rifle in the family's barn. T.S. was with him, but he never speaks of this matter. When it happened, he was measuring the scale of the gunshots for an experiment, and he doesn't understand the cause of the misfortune.
One day, T.S. receives an unexpected call from the Smithsonian Institution. They tell him that he is the winner of the very prestigious Baird Prize for his invention of the perpetual motion machine. He is invited to a reception in his honor where he is expected to make a speech. Without telling anyone, he leaves the ranch and jumps onto train across the United States to reach Washington, D.C.