Jiangcheng Secret Whistle: 1938

June 1938, Wuhan. As a radio expert studying in Germany, Zhou Yu'an was ordered to sneak into the telecommunications department of Hankou Station of the Military Command. On his first day on the job, he intercepted a strange signal on band 17 - signed with only one letter: "H". He didn't know that this radio guidance system called "Tingfeng" was created by his uncle Huang Jun who had been executed. He didn't even know that his immediate boss, Lin Yuanfan, was his brother who had been separated for ten years. One is latent and the other is in power. One is searching for the cause of his father's death in the dark, and the other is looking for the murderer with a scar on the left side of his face in the open. The brothers meet again but dare not recognize each other. The signal of band 17 is still ringing. The countdown to 0728 has begun. And the man with the scar on the left side of his face was hiding deep in the military compound, waiting for them to fall into their trap.