During the Anti-Japanese War in the 1940s, Linhai City was an important coastal city under the influence of various forces. This city not only has complex commercial exchanges, but is also an important military supply and intelligence base for the Japanese army. It is also a key area for secret competition between the Kuomintang and the Communist Party and the anti-Japanese forces of all parties. The Japanese secret service here attempts to consolidate its rule in China by collecting intelligence and destroying anti-Japanese organizations. However, our underground workers risk their lives and lurk inside the enemy camp, working tirelessly to deliver intelligence and disrupt the enemy's conspiracy.