In the Jiayang Valley of Sichuan, southwest China, a narrow gauge steam railway built seventy years ago to haul coal remains the only way in or out. There are no roads, so the 19-kilometer line carries schoolchildren, workers, and pigs to market crammed into small, unglazed carriages behind aging steam locomotives. The film follows villagers as they fight to keep the railway alive now that the coal mine it once served has shut down. With no manufacturer left to supply spare parts, they hand-fabricate what they can, but a failing boiler is beyond their workshop's capacity, and the crew tracks their search for a company willing to build a replacement, and then the logistics of hauling something that large into a valley with no roads. Interviews with residents and railway workers sit alongside footage of the trains threading through the mountains. Set against China's bullet trains and maglev lines, the film turns to the quieter, poorer country that still surrounds them.