After the war, there were Japanese who worked for the founding of the People's Republic of China. Whether they liked it or not, they stayed on the mainland and contributed to China's development as railroad and steel mill engineers, military doctors, and nurses.

China had an urgent need to improve its infrastructure, particularly in the repair and construction of its railroads. The Chinese were particularly interested in those who had worked for the "Manchurian Railway" (South Manchuria Railway). While many Japanese were returning to their homeland, they were sent to western China and ordered to build a railroad. The fragile geology and complex topography of the region made the construction of many bridges and tunnels a difficult undertaking. The Japanese railroad workers worked hard while passing on their skills to the Chinese.

Through the few witnesses who knew the history of the project at the time, this film reveals the "heart" of the people of the two countries and the old man who tried to pass it on to future generations, revealing the hidden story of the great project and the postwar history of Japan and China.