Preston Clearwater has been a criminal since stealing two chain saws and 1,600 pairs of aviator sunglasses from the army during the Second World War. Back on the road in postwar North Carolina, now a member of a car-theft ring, he picks up hitchhiking Henry Dampier, an innocent twenty-year-old Bible salesman. Clearwater immediately recognizes Henry as smart but gullible, just the associate he needs--one who will believe Clearwater is working undercover for the F.B.I.; one who will drive the cars Clearwater steals as Clearwater follows along in his own car at a safe distance. Henry joyfully sees a chance to lead a dual life as a Bible salesman and a G-man.

During his hilarious and scary adventures, Henry grapples with doubts about the Bible's accuracy, and we learn of his fundamentalist upbringing, an upbringing that doesn't prepared him for his new life. As he falls in love with the captivating Marleen Green and questions his religious training, Henry begins to see he's being used--that he is on his own in a way he never imagined.