小小少年T.S. 斯派维（凯尔·凯特莱特 Kyle Catlett 饰）生于蒙大拿州一个偏远牧场，他有一颗聪明绝顶的大脑，酷爱制图学和科学图解，年仅十岁就发明了永动机。他的父亲（考乐姆·吉斯·雷尼 Callum Keith Rennie 饰）是个狂热的牛仔迷，搜集关于西部牛仔的一切；母亲（海伦娜·伯翰·卡特 Helena Bonham Carter 饰）是一位生物学博士，潜心投入到昆虫研究中；而姐姐则是一个最普通不过的正常人，她常常为生在这个一屋子怪人的家里而烦恼。T.S.原本还有一个异卵双胞胎弟弟雷顿，去年死于一场意外。 　　这天，T.S.接到一个来自史密森学院的电话，告知他被授予了世界科学大奖贝尔德奖，并邀请他到华盛顿演讲。于是，十岁的科学奇才T.S.斯派维，偷偷爬上了货运火车，独自踏上了穿越美国的奇异旅行。T.S. Spivet lives on a ranch in Montana with his mother who is obsessed with the morphology of beetles, his father (a cowboy born a hundred years too late) and his 14 year-old sister who dreams of becoming Miss America. T.S. is a 10 year-old prodigy with a passion for cartography and scientific inventions. One day, he receives an unexpected call from the Smithsonian museum telling him that he is the winner of the very prestigious Baird prize for his discovery of the 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 U.S.A. to reach Washington DC. There is also Layton, twin brother of T.S., who 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.