1939, Nanjing. Shen Zhiyuan is the most silent codebreaker in the Translation Section of the Wang Puppet Agent Headquarters. He was able to capture the Japanese army's mobilization codes from thousands of secret messages, and he could also see through the flaws in disguised identities at a glance. But he didn't dare to laugh - three months ago, the secret message he personally decoded led to the destruction of an underground party contact station and the death of six people, including his fiancée. Now, the Japanese army's "Sakura Secret Order" is about to be launched, and the lists of hundreds of lurkers are facing leaks. Shen Zhiyuan must decipher the new password within 72 hours, otherwise the key will become invalid and all the hidden clues will be exposed. But for every person he saved, one would die because of him. When Shuichi Sato pointed a gun at the head of the orphan Xiao Shitou, forcing him to hand over the code book; when the military commander Yao Jin laid a trap for him to fall into the net; when his hands were pierced by bamboo sticks and blood dripped on the decoding paper - Shen Zhiyuan finally understood that the only thing he could trust in this isolated city was his own brain. "If I kill you, they will be safe?" Gu Mengchan asked him with red eyes. Shen Zhiyuan smiled, with blood bleeding from the corner of his mouth: "No. Kill me, and they will die."
