Lin Yu, a passionate young man, was selected by Shanghai Station Master Qi Yannian and sneaked into Shanghai Station with the goal of finding the mole "Shen Yue" hidden in the archives room. However, during the investigation, Lin Yu was rescued from fire and water many times by the "mediocre" archives director Gu Jingshan, and witnessed with his own eyes the huge sacrifice Gu Jingshan made in order to resist Japan and save the country. At a time when the nation was dying, Lin Yu, under the guidance of Gu Jingshan, gradually saw clearly the corruption of the National Government and took over the fire of "Shen Yue". He lurked alone in the heart of the enemy, experienced the War of Resistance and Liberation, and became a nail that never rusts in the baptism of blood and fire.
