Instead of taking a gap year, disgruntled high school graduate Sam Harrison accepts an offer from his eccentric grandfather, Gus, to ride with him across the country on a pair of restored vintage BMW motorcycles to visit an old friend in California. While riding the vast stretches of open road, Sam decides to listen to a Don Quixote audio-book, as suggested by Dr. Fitz, the one teacher he had admired while in school. Meanwhile, Gus gradually reveals the details of a highly unusual criminal case he was involved in while a young prosecutor in New Mexico. As the two stories unfold, Sam begins to see similarities between the fictional knight errant of yesteryear who chased windmills and his grandfather, who chased corporate giants.