Su Bi signaled the guard to go forward and knock on the door, while he carefully stood behind, protecting Ning Xihua.

This family was unscathed in the area most affected by the epidemic. Either they were involved in the poisoning, or they had some special method to contain the epidemic.

"Who is it?"

The door was opened quickly. A young woman came to open it. She was frightened when she saw so many people outside the door.

The guard explained the purpose of their visit to her for a long time before the woman let them all into the house.

After entering the house, Ning Xihua looked around and found that it was just an ordinary house with nothing special about it.

The woman's husband also came out to greet him. Seeing that the visitor had a noble temperament, he was trembling with fear for fear of offending the nobleman.

"Don't be afraid. We are just routinely checking to see if there are any sick people in your family and whether they need to be isolated or sent to centralized treatment."

The man didn't really believe it after seeing the scene, but he still answered truthfully.

"To reply to your words, no one in my family is infected with the disease."

Ning Xihua was even more surprised when she heard this. "Is there not even anyone with a cough? How many people are there in your family? Are there any elderly or children?"

The man saw that although Ning Xihua was wearing a veil and spoke in a friendly tone, her overall demeanor could not be faked. Moreover, the man who had been protecting her looked like someone who was not someone to be trifled with.

Therefore, he still replied respectfully, "There are five people in my family. My father is bedridden due to his bad legs. I have a son and a daughter. The son is seven years old and the daughter is five years old. My wife and I make a living by doing odd jobs for others."

It is really strange that no one in the family, including both old and young, got sick in this quiet alley.

Su Bi had been listening to Ning Xihua's negotiation with this man without saying anything, but now she suddenly asked, "Aren't you from Yizhou?"

The man was stunned by the question, and then replied, "I am indeed not a native of Yizhou. My ancestors originally settled in the northern border, but because my father was ill, Yizhou was warm and suitable for recuperation, so I moved to Yizhou with my family five years ago."

Northern Xinjiang?

Ning Xihua was touched by this place name. Su Bi said that the information revealed by Xiao Baihua was "Yizhou" and "Northern Xinjiang". Could it be that this epidemic is related to Northern Xinjiang? But I have never heard of a similar plague in Northern Xinjiang?

The guard who had quietly entered the house to search while they were talking also returned to Su Bi's side and shook his head at him.

There was nothing unusual in this home.

Ning Xihua was still trying to figure out how this epidemic could be connected to Northern Xinjiang, but she accidentally saw a small stove burning in the yard.

"What's that? If no one in your family is sick, why are you boiling medicine?"

The man looked in the direction Ning Xihua pointed and immediately knelt down to explain.

"I dare not lie to you! No one in my family is sick. The water in the stove is just the swordgrass water that we have always boiled."

The woman was so frightened that she knelt on the ground. "Yes, sir, my family all migrated from the Northern Frontier. In the border towns of the Northern Frontier, it is a custom to boil this swordgrass water for drinking or bathing. My family is used to it, so we boil it often!"

Su Bi turned around and looked at the guards beside him. These soldiers had been stationed in the northern border for many years, so they could tell whether they were real or fake at a glance.

The guard bowed and replied, "Your Highness, some towns in the northern border do have the custom of boiling water with sedge grass. They believe that sedge grass can not only drive away the cold, but also ward off evil spirits. So many people are used to boiling sedge grass water to bathe when they encounter bad things, or boil sedge grass water to ward off the cold in winter."

Ning Xihua suddenly thought of something, "Have you been making this swordgrass water to drink these past few months?"

The woman replied tremblingly, "Yes, although the climate in Yizhou is warm, my father still suffers from pain in his legs and feet after the beginning of winter due to the weather. I have been boiling water with swordgrass for my father to dispel the cold since the beginning of winter, and the whole family has also been drinking it."

Ning Xihua's eyes lit up. "Do you have any extra sword grass at home? Can I borrow some?"

The woman immediately agreed, "Also, this thing is not worth much. I will go get it for you now."

After saying that, he immediately turned around and went back to the house to get it.

Ning Xihua looked at Su Bi, feeling quite excited.

Su Bi also understood her thoughts and smiled at her, "Don't worry, we will go to Yu'an Hall now."

After getting the things, the two of them immediately rushed to Yu'an Hall to find Doctor Xu.

At this moment, all the famous doctors in Yizhou and the famous doctors brought by Su Bi from the capital were on standby in Yu'an Hall.

Two hours later, Doctor Xu came back excitedly to report.

"My Lord, I boiled the swordgrass into a thick juice and fed it to several dying patients. Their fever has begun to subside. The swordgrass is useful!"

Ning Xihua also jumped up excitedly, wishing she could grab Su Bi and spin around happily three times.

Su Bi was also looking at her and smiling. She then remembered that she was still a princess. After calming down, she immediately straightened her clothes.

"Does Yizhou have enough Jianmao in stock?"

Doctor Xu leaned forward and replied, "It's a shame to say that this sword grass is produced in the northern border and is mostly used to dispel cold and ward off evil spirits. It is not included in the scope of orthodox herbal medicine, which is why it was overlooked by me. Because sword grass is mostly sold as daily necessities for the public, there is not much stock in Yizhou."

Hearing this, Ning Xihua became worried again.

Su Bi comforted her, "It's okay. I have asked people to transfer all the Jianmao in the surrounding cities to Yizhou for urgent use. I will send a letter to the capital later and ask Prince Ning to help and order the court to transport Jianmao from the northern border."

It turned out that Su Bi had anticipated that this sword grass might be useful before the results came out, and had already asked people to transfer sword grass from several surrounding cities.

"As long as there is a cure for this epidemic, it will only be a matter of time before the plague is cured and Yizhou is unsealed."

Ning Xihua nodded, and suddenly felt full of confidence.

Doctor Xu standing by lowered his head in embarrassment. He was too excited just now, and his first reaction was to report to the princess out of habit. He completely forgot that his real master was still there. Fortunately, the prince didn't seem to care.

The discovery of Jianmao brought hope to the entire Yizhou plague.

The swordgrass from the surrounding towns was sent to Yizhou one after another in order from near to far.

All the delivered swordgrass was given priority to seriously ill patients, which significantly reduced the number of deaths in Yizhou.

Of course, faced with the appearance of life-saving medicine, people's hearts began to waver. Regardless of whether they were sick or not, everyone couldn't wait to take the herbal medicine to save their lives.

That day, Song Yi hurriedly came to report to Ning Xihua, "Princess, a group of noble families in the city surrounded the mansion. They are clamoring for you to come out."

It turned out that the head of the Li family, a large aristocratic family in the city, fell ill, so Li Cheng, the eldest son of the Li family, joined forces with several young men from official families and gathered a lot of people to go to Ning Mansion to cause trouble.

They knew that although Zhao Yukang was the governor of Yizhou, Princess Yuexi's words were the most influential in the entire Yizhou.

They did not dare to look for His Royal Highness the Crown Prince who had already entered the city. They just thought that Princess Yuexi was a woman, and from a noble family like them. If they made a little trouble and explained things to her with reason, she would surely be submissive and release her sword and thatch.

There was a lot of noise in front of the Ning Mansion. The city guards rushed over and saw that they were all children of the city's noble families. They didn't dare to take action for a while.

Ning Xihua in the mansion heard Song Yi's report, but she was not panicked.

"What's the hurry?"

With the boss around, is it her turn to step in and take care of things? Just sit back and relax.