Martin Strel is a Slovenian endurance swimmer in his fifties, overweight and fond of wine, who has already swum the length of the Mississippi, the Danube, and the Yangtze to draw attention to the rivers' pollution. Here he takes on the Amazon, 3,375 miles of it, aiming for the longest continuous swim ever recorded. His son Borut, who speaks English and manages the support boat and the logistics, travels with him, while director John Maringouin films the trip as it happens rather than as a staged expedition. The river supplies real hazards on camera: piranhas and other predatory fish, stretches of rapids, and water contaminated enough to threaten his health directly. Strel's physical and mental state visibly deteriorates as the days accumulate, and the footage tracks that decline alongside the environmental point he set out to make. The film sits somewhere between character study and survival story, watching a strange, stubborn man push a publicity stunt past the point where it stops looking like one.