The Courtyard House: The story begins with He Yuzhu beating up the White Widow.

After Jiang Chuan walked over, He Yuzhu pointed at him and said, "Did you see that guy in the black Zhongshan suit?! I saw him before Liberation. He was wearing the officer's uniform from the bald guy's side."

Yu Feilong asked, "Zhu Zi, did you look carefully?!"

He Yuzhu retorted, "Don't you believe my eyes?!"

Wu Jiajie and Yu Feilong immediately recalled the incident with the enemy agents. Wu Jiajie said, "Leave the rest to us!"

"Alright! I'll leave it to you guys. I'm going to buy groceries." With that, He Yuzhu ran straight into the market. Wu Jiajie and Yu Feilong followed Jiang Chuan in perfect unison.

About half an hour later, He Yuzhu had just finished buying groceries and was about to return to the Military Control Commission when he ran into Yang Ruihua, who was also buying groceries. He Yuzhu greeted her with a smile, "Aunt Yang, buying groceries?"

Yang Ruihua asked, "Zhu Zi, what vegetables did you buy?!"

He Yuzhu replied, "What kind of vegetables can I buy?! Just some ordinary vegetables."

Yang Ruihua's eyes lit up when he saw the meat in the basket. He said, "Zhuzi, this piece of meat is pretty good!" As he spoke, Yang Ruihua reached out to take the meat.

He Yuzhu stepped aside and said, "Aunt Yang, I bought the meat from that butcher stall over there. When I came by just now, I saw there was still quite a bit of meat left. If you want some meat, hurry up and go, or it'll be gone." With that, He Yuzhu turned to leave. But how could Yang Ruihua let the meat slip through her fingers?! Yang Ruihua quickly stopped He Yuzhu, saying, "Yuzhu, I'm heavily pregnant and it's inconvenient for me. Why don't you give me the meat you're holding? You can go buy some more!"

He Yuzhu looked at Yang Ruihua, who was holding his hand, and said, "Aunt Yang, are you trying to rob me?!"

Yang Ruihua immediately released his grip, like a frightened bird, and said, "Zhu Zi, you can't just say things like that!"

He Yuzhu said, "I'm talking nonsense?! How do you know I'm talking nonsense if you don't do it?! Aunt Yang, others may not understand the family traditions of the Yan family, but do you think I don't?! Don't try to fool me!" After saying that, He Yuzhu was afraid that if he was a step too late, he would be entangled by Yang Ruihua, so he walked out of the market gate as fast as he could.

Watching He Yuzhu's retreating figure, Yang Ruihua regretted her slowness. If she had acted faster and grabbed the meat, even if she couldn't take it home, her hands would have gotten quite oily. She could wash the oil off her hands later and use the oily water to cook, adding a little something extra for her family. Unfortunately, it was too late. Thinking this, Yang Ruihua, her belly protruding, immediately walked towards the meat stall. However, when she arrived, the meat was sold out, and the stall owner had already left.

Meanwhile, when He Yuzhu returned to the Military Control Commission, Wu Jiajie and Yu Feilong followed Jiang Chuan to Houhai. Wu Jiajie stood behind a tree, and Yu Feilong stood beside a large tea stall, drinking tea. But both of them kept their eyes fixed on Jiang Chuan.

After a while, once the people sitting on the bench under the streetlights had left, Jiang Chuan immediately went to sit down on the bench. He furtively glanced around, then took out his cigarette case, pulled out a cigarette, and lit it. After about three or four minutes, seeing that no one was paying attention, Jiang Chuan immediately threw the cigarette butt on the ground, stomped it out, and pulled a folded piece of paper from his pocket, stuffing it into the crevice of the bench back. He sat there for a while longer before leaving.

Wu Jiajie and Yu Feilong exchanged a glance. Yu Feilong followed, while Wu Jiajie walked to the bench and sat down. After Jiang Chuan had gone some distance, Wu Jiajie observed his surroundings while feeling around on the bench. Soon, Wu Jiajie found the note Jiang Chuan had left behind tucked away in a crevice.

Wu Jiajie took out the slip of paper, opened it, and saw a series of numbers written on it. Wu Jiajie immediately pulled out his work notebook, copied down the numbers, and then put the slip of paper back in the crevice. Then, pretending nothing had happened, Wu Jiajie leisurely left, humming a song.

After walking for a while, Wu Jiajie immediately turned back and found a good spot to continue watching the bench. Before he knew it, an hour had passed. Yu Feilong returned to Houhai, found Wu Jiajie, and asked, "What's the situation now?!"

Wu Jiajie retorted, "Why are you here?!"

Yu Feilong said, "I followed that man to Xibanqiao. I saw him enter a courtyard house. Later, I found out that the man's name was Jiang Chuan, and he worked as a boiler operator at the Hongxing Steel Rolling Mill."

Just as Wu Jiajie was about to speak, he saw a scavenger walk to the bench and sit down. About seven or eight minutes later, the scavenger left. Wu Jiajie immediately went to the bench and looked towards where the note had been hidden. Seeing that it was gone, Wu Jiajie hurriedly said, "Quick, chase after that scavenger!"

Unfortunately, the scavenger was very cautious, leading Wu Jiajie and Yu Feilong around the alley several times. Wu Jiajie and Yu Feilong lost track of him. Left with no other option, Wu Jiajie and Yu Feilong had to return to the police station to report.

"Xiao Wu, Xiao Yu, what brings you two here?!" Zhang Qiang had just returned from the military control commission's canteen with his food when he saw Wu Jiajie and Yu Feilong coming in. Wu Jiajie said, "Chief, don't even mention it! That brat He Yuzhu conscripted us."

Zhang Qiang asked curiously, "What exactly happened?!" After hesitating for a few seconds, Zhang Qiang said, "Let's talk in my office."

"Oh!" Wu Jiajie responded and, together with Yu Feilong, followed Zhang Qiang toward the director's office.

Upon entering the office, Yu Feilong, who was at the back, closed the door. Wu Jiajie then recounted the events to Zhang Qiang and handed him the string of numbers he had copied down. Yu Feilong added what he knew. After listening to their accounts, Zhang Qiang said, "I really didn't realize He Yuzhu had such a good memory."

Wu Jiajie asked, "Chief, what should we do next?!"

Zhang Qiang said, "Hongxing Steel Rolling Mill is a pilot unit for the joint public-private ownership. Absolutely nothing can happen to it. Now that we know Jiang Chuan has a problem, I will notify the mill's security department to strengthen their defenses! We must keep a close eye on Jiang Chuan. We can't let him have a chance to sabotage the mill. As for that scavenger, besides waiting for him to reappear, we also need to intensify our investigations and find a way to dig him out."

"Yes!" Wu Jiajie and Yu Feilong responded in unison and left Zhang Qiang's office. After they left, Zhang Qiang, without even eating, picked up the phone on his desk and dialed a number. The call connected shortly after. Zhang Qiang said, "Is this the main switchboard for Hongxing Steel Rolling Mill?! Transfer me to the head of the security department's office!"

Not long after, the voice of Mao Yongnian, the head of the security department of Hongxing Steel Rolling Mill, came from the other end of the phone: "This is Mao Yongnian, who is this?!"