In 2035, Korea is celebrating 10 years of reunification: a decade earlier, North and South Korea worked together to extinguish a forest fire in the demilitarized zone, and this collaboration finally brought peace between the countries. Steven, an American director, travels to the site to film a documentary about the reunification. He begins investigating a mysterious green light that reportedly appeared during the fire, and finds a huge secret of this event and about the demilitarized zone.