Spanning nearly 500 miles across the Rocky Mountains, the Colorado Trail is an epic, arduous route through some of America's most breathtaking natural grandeur. In the summer of 2022, Fr. John Nepil, priest-theologian and mountaineer, set out to traverse the entire trail as a "thru-hike" with a trio of companions, accompanied along the way by an eclectic rotating cast of priests and young people. This memoir, which is simultaneously a theological reflection on life, Christianity, and the mountains themselves, is the fruit of that pilgrimage. Drawing on great thinkers of the past century, including Luigi Giussani, Dietrich von Hildebrand, and Hans Urs von Balthasar, Fr. Nepil offers a "first ascent" a new route where Catholic theology meets alpine adventure. In his telling, the Catholic worldview offers the fullest spiritual vision of the backcountry, and the backcountry, in turn, reveals itself as a privileged setting for Catholic formation. Seen from the trail, the Catholic faith comes alive as an Incarnational worldview where we rediscover humanity, creation, and God. This is a rich theological guidebook for all Catholic lovers of the great outdoors--particularly the mountains--and for all who see and seek God in the stark majesty of the natural world.