The roughly 700-mile Mexico-United States fence is a massive reminder that, in many ways, the border between the two countries is a conflict zone where surplus from the Vietnam War – militarised weapons, ground vehicles, helicopters and heat sensors – are now employed to pursue immigrants headed northwards. Walleyball finds the eclectic US filmmaker Brent Hoff making a playful yet powerful plea for humanity where Tijuana meets San Diego, initiating a friendly game of over-the-fence volleyball with two Mexican beach-goers amid the unforgiving hum of helicopters.