Opening with the Japanese national anthem, the film traces Taiwanese labourers in Okinawa, mass student labour in the Sakishima Islands, and Shōwa-era (1926–1989) coal mining on Iriomote. Travelling from Yonaguni to Taiwan, it reaches a Tayal village shaped by the Musha Incident (1930), where the noontime bell was replaced by the Imperial Japanese military song, 'Umi Yukaba'.