Let's start with what happened recently.

Before Ling Shu followed Yue Dingtang to the northeast, he was also rarely at home, only coming back to eat and sleep. He didn't notice much change at home.

But Ling Yao noticed something was off.

Zhou Sa worked at the municipal government, and his commute time was fixed. 

Within fifteen minutes after Ling Yao served the last dish, her husband would always open the door.

But one day, this routine was suddenly broken.

Zhou Sa started coming home late.

At first, Ling Yao didn't suspect anything when he said he had work to do. 

But then it became a pattern, with him coming home late three, four, five, or even six days a week.

Ling Yao began to have doubts. 

She wasn't a traditional housewife who followed the three obediences and four virtues. During the turbulent days of the Ling family, when Ling Shu was still young, she took on the burden of supporting the family on her own.

One time, while Zhou Sa was still at work, Ling Yao waited outside the municipal government for about half an hour until she finally saw him come out.

He was alone, in a hurry, and had no colleagues or friends with him. He hailed a yellow cab and headed in the opposite direction of their home.

Ling Yao chased after the car on foot but quickly lost it. 

The second time, she hired a yellow cab to wait in a hidden spot outside. As soon as Zhou Sa got in the car, she instructed the driver to follow at a distance until he stopped and entered a small villa. The gatekeeper seemed familiar with him, chatting and laughing with a warm attitude.

Ling Yao glanced around and saw that all the nearby houses were small Western-style buildings with foreigners coming in and out.

Living in the concession was not uncommon, but being able to live next to a foreigner with status was not something ordinary people could achieve. 

Either they had to have money or they had to know people in the concession.

"At the time, I kept my eyes peeled and waited across the street until it was dark. Then I saw your brother-in-law come out. Can you guess what I saw? A woman sent him off at the door, and they bid farewell with reluctance. The woman's expression was quite sad."

Ling Yao sneered as he spoke. "I rushed here as fast as I could, just to arrive before your brother-in-law. When he came back, I asked him where he had been and why he was so late. He said his boss had kept him for some work and he lost track of time."

"At that moment, I wanted to argue with him, but I thought about how he had treated me well these past few years, so I held back. Who knew that he would only get worse, coming home late more and more frequently. You saw what happened today, and I..."

Ling Yao couldn't hold back any longer and started crying into her handkerchief.

Ling Shu patted her back.

"Sis, you might have misunderstood your brother-in-law today. I met him at Yue Dingtang's house and we came back together. There was no more than a two-hour gap between us, and if he had gone to the concession to meet someone, he would have had to rush back to make it in time. It doesn't make sense, does it?" 

Ling Yao looked up and exclaimed, "Couldn't they have met in a café instead?"

Ling Shu replied, "But my brother-in-law isn't the type to do something like that, is he?"

Ling Yao retorted angrily, "I knew it, men always stick together!"

Ling Shu could only shake his head helplessly and said, "Sis, I also think that our brother-in-law must be hiding something from us. Regardless of where that woman came from, the fact remains that he left halfway through the night to meet her. But it's highly unlikely. Just think about it, if you were him, you just left your brother-in-law's place and then rushed off to meet another woman. He doesn't even have a car, at most he could only take a taxi. Not to mention the time it takes to travel back and forth, he would only have less than half an hour to meet her. How much could they possibly say to each other? He looked really hungry just now, it's obvious he didn't have dinner before coming back." 

Ling Yao asked, "So where did he go after leaving you?"

Ling Shu replied, "Didn't you ask your brother-in-law? What did he say?"

"He said he saw someone fainting on the road, so he went to help and settled the person in a roadside teahouse. He only came back after making sure the person was okay," Ling Yao said.

Ling Shu chuckled, "That sounds like something your brother-in-law would do."

"You're still laughing! How can you still laugh!" Ling Yao pounded the bed in anger, "I work so hard to keep this family going! Your brother-in-law keeps pushing me to have a child, don't I want to have one too? I appreciate his kindness towards me, and I also want to leave a legacy for the Zhou family. But, I've seen so many doctors and nothing has happened. What can I do? Your brother-in-law tells me it's okay, but then he goes and looks for a mistress behind my back!" 

As she spoke, a wave of sadness washed over her. From anger to sorrow, tears streamed down her face once again.

"I knew it. He still resents me deep down. He must think I'm too strict and harsh with him on a daily basis, so he goes out and finds those gentle and sweet women. I've heard about it. His immediate boss, the director of that building, keeps two mistresses on the side. His wife knows, but pretends not to. I never thought your brother-in-law, who hasn't even made it big yet, would become this kind of person!"

"Younger brother, what should I do? If he really has another woman outside, what should I do?"

"Sister, don't worry. If your husband really did something wrong, I won't let him off the hook. We can always get a divorce. I'll take care of you!"

Upon hearing Ling Shu's words, Ling Yao did not feel happy, but shook her head. 

"Divorce? Have you ever heard of a good woman who would divorce? In ancient times, this would mean being abandoned. My reputation will be ruined. How will you find a wife in the future?"

Ling Shu sighed, "It's not called being abandoned in ancient times, it's called a mutual separation. Besides, sister, it's a new era now. We don't follow those old-fashioned customs anymore! Divorce is so common these days. A few years ago, even the emperor got divorced. The Miss of the Sheng family fought with her brothers over inheritance in court, and the whole world knew about it. There's nothing shameful about fighting for your legal rights. If my future wife looks down on us because of this, what's the point of this marriage?"

Ling Yao choked up, "You make it sound like he really has someone else outside!"

Ling Shu: ... 

"I'm just telling you the worst-case scenario first. Even if it's divorce, what is there to worry about? Besides, you've been married to your brother-in-law for several years, so you should know him well. Maybe that woman owes him money, or maybe his boss asked him to find her. It's meaningless to speculate without asking first."

Ling Yao replied, "I dare not ask. I'm afraid that if I do, I won't be able to handle the consequences."

Ling Shu stood up and declared, "Then I'll go ask!"

Ling Yao quickly grabbed him and said, "Don't ask. What if he admits to it? What if, by chance, we wrongly accused him? Even though your brother-in-law usually has a good temper, if he finds out that I suspect him, he'll definitely be angry!"

Ling Shu pursed his lips and asked, "So what do you want to do?"

After thinking for a moment, Ling Yao said, "You should investigate secretly." 

"Me?" Ling Shu pointed to himself, surprised that the trouble had finally found its way to him.

Ling Yao said, "Yes, you solved big cases before, and now you're working at the police station. Perfect. Investigate quietly, don't let your brother-in-law find out. Find out who that woman is and what her relationship is with your brother-in-law!"

Ling Shu sighed, "Sis, I'm just a small police officer. I don't have much power to investigate. Besides, can those cases compare to my brother-in-law's affairs? At best, it's just..."

Before he could finish saying "family matters," Ling Yao stared at him, tears welling up in her eyes.

Ling Shu raised his hands in surrender. "I'll investigate."

But how to investigate? 

Where to start? 

That was the question.

Three days later, Ling Shu realized that this might be a problem even more difficult than solving the case of Zhen Congyun. 

At the same time, Yue Dingtang also discovered that Ling Shu's behavior was strange.