In the autumn of 1937, on the eve of the fall of Suzhou. Cheng Moshu, an ancient book restorer who looks weak on the surface, carries out a top-secret mission under the dust of a crowded library: using the restoration and transportation of ancient books to deliver key information to the front line. There is no smoke in his battlefield, only the fragrance of ink and secret words; his weapons are not guns, but penknives and minds. When a Japanese military force deployment plan related to the survival of the Jiangnan defense line unexpectedly appeared, Cheng Moshu's peaceful daily life was completely broken. He must complete this silent life-and-death express under the close surveillance of Japanese and puppet spies and the shadow of possible traitors within.
