Tancrède Melet and Julien Millot are two French highliners, practitioners of a sport that combines climbing, slacklining, and tightrope walking on webbing rigged between cliffs, peaks, or other high points with nothing but a harness for backup. The film follows the pair as they push the sport toward what they call its next evolution, rigging longer and more exposed lines and attempting moves beyond what has been done on a highline before. Rather than treating the footage as pure spectacle, the film stays close to the friendship between Melet and Millot, showing the planning, the rigging work, and the trust required when one person's mistake can kill the other. Their partnership, built over years of shared rigging and shared risk, is presented as the real subject, with the aerial footage of their walks serving as evidence of what that trust makes possible.