History graduate student Li Yi accidentally traveled to the Jizhong Plain in 1942, just as the Japanese army launched the brutal "May Day raids." In desperate situation, he was rescued by the mysterious veteran Li Tieshan and brought into a tunnel network extending in all directions. In this invisible underground world, Li Yi personally experienced the threats of hunger, injury and death, and also witnessed the amazing wisdom and tenacity of the Chinese people in desperate situations. From a powerless scholar to a warrior who took up arms and used modern knowledge to participate in the struggle, Li Yi, together with Li Tieshan, Xiu Qin, Erga and other militiamen, dealt with the enemy in the dark tunnels, guarding the last fire of survival with their lives. This is a battle about survival and belief, a soul-stirring legend of tunnel warfare.
