Special Forces veteran Travis Combs just wanted to forget his weary years of leading combat missions while taking an extended rafting trip through the Grand Canyon. As he and his group complete a 22-day trip on the Colorado River, they find the world has unraveled from a deadly pandemic. Now, he has to show his small band how to live off the land and cross the rugged Arizona desert, while evading blood-drinking zombies, gangs of cartel bikers, and a rogue government agency.