In 1938, two young newlyweds and their good friend set off from Paris on a bold adventure: to be the first to take kayaks down America's famous whitewater river, the mighty Colorado. Setting off with film cameras, loaded with color film (before the first Hollywood color movie), they documented their journey, which took them on a cross country road trip across the US, a 1,000 miles of a first kayak decent down the Green and Colordao, and eventually back to France, at the outbreak of WWII. For more than 75 years their story had been lost--overshadowed by WWII, and forgotten--until filmmaker Ian McCluskey stumbled on an obscure roadside historic plaque. Curiosity and a call to adventure take hold, and he decides to learn how to white-water kayak to follow the path of the "voyagers without trace." In the process, he uncovers unexpected connections to the French Resistance, the French Riviera, and the spirit of adventure accessible to all.