本書作者從空中攝影及田野訪查記錄中，在飛閱「臺三線」的自然、人文與地景的同時，也能窺探先民當年面對族群關係緊張時期的艱辛。以歷史的角度，從台中東勢到桃園龍潭這段「臺三線」，就是土牛紅線（土牛溝）、隘勇線、古道運輸線。 臺三線沿線地區，產業是多元的，需要複雜的技術，也結合大型的商業行為；相對於平原地區，傳統都以稻米為主，較為安定。印證了在平原安全無虞，但只能種稻，山裡頭未臻之地雖然佈滿危險，但是也充滿著機會的寶庫。
英文內容大要： From the director's aerial documentary film and field survey records, the filming of "Taiwan Route 3" did not only show that of Taiwan’s nature, humanities and landscapes, but also gave a glimpse of the hardships when the early settlers encountered great ethnic tensions at the time. From a historical perspective, the "Taiwan Route 3" extends from the Taichung Dongshi to the Taoyuan Longtan is the aboriginal boundary (Tu-niu Ditch), the Defense line of frontier gourd boundary and the ancient route transportation line. In the areas along the Taiwan Route 3, the industry is diversified, requiring complex technologies and integrating large-scale commercial activities. Compared with the areas in the plains, the traditional industry is dominated by rice cultivation. It proves that it is safe and sound to grow in the plains, but only to grow rice. Although the unfinished land in the mountains is full of danger, it is also full of treasures.