Tatsuo Senō led the firefighting force in his village on Shikotan Island. He resided there with his two sons, Junpei and Kanta, and his fisherman father, Genzō. After Japan's surrender in World War II, his non-military role as a civil defense coordinator allowed him to escape initial Soviet capture.

During the Soviet occupation, Tatsuo spearheaded the covert distribution of emergency rice reserves from hidden military stockpiles to aid starving villagers, directly defying Soviet resource control. His arrest followed when his brother Hideo's smuggling attempt exposed the food network. Tatsuo was imprisoned separately from his family.

While imprisoned at a Soviet camp near Maoka in Karafuto, Tatsuo experienced a fleeting reunion with his sons and their teacher Sawako during their escape effort. In this final meeting, he made a solemn promise to reunite with them despite the bleak circumstances.

Decades later, his grave is revealed alongside Kanta's during Junpei and Sawako's return to Shikotan, confirming his post-war death. Tatsuo's legacy endures through Junpei's memories and the symbolic naming of Junpei's sons after characters from Kenji Miyazawa's "Night on the Galactic Railroad," honoring Tatsuo's personal reverence for the story.