Xu Yuehuai gripped the medicine bottle tightly, a warm feeling welling up inside her. She knew that the Ghost Doctor was not only a friend who fought alongside her, but also her most trusted partner in this complex world.

She murmured softly, "Thank you, Ghost Doctor."

The Ghost Doctor gently waved his hand, indicating that she didn't need to say anything more. His deep eyes revealed his admiration for Xu Yuehuai's resilience and determination. He knew that this woman would never easily back down because of a little danger. All he could do was to do everything in his power to provide her with a solid guarantee.

The two fell into a brief silence, which Xu Yuehuai suddenly broke: "Ghost Doctor, do you think this fake medicine incident is related to that mysterious 'Four Kingdoms Slaughter' organization?" Her brows were furrowed and her expression was solemn.

The Ghost Doctor pondered for a moment, then slowly said, "It is indeed difficult to draw a conclusion. The 'Four Kingdoms Slaughter' organization acts strangely and unpredictably, and its purposes and methods are often hard to fathom. But judging from the circumstances of Li the Cripple's murder, this matter may indeed be related to them."

A resolute glint flashed in Xu Yuehuai's eyes: "If that's the case, we can't stand idly by. We must find out the truth as soon as possible and bring those culprits who have endangered the peace of the four nations to justice!"

The Ghost Doctor said gravely, "You're right. But we can't show ourselves yet, lest we alert them."

“I will keep an eye on it. Also, I plan to arrange for some people to secretly monitor Song Luo and see what she’s up to.” Xu Yuehuai clenched her fists, her mind made up.

The Ghost Doctor did not object. "This arrangement is appropriate. However, you need to be extra careful and avoid putting yourself in danger."

Xu Yuehuai smiled slightly, revealing a confident smile: "Don't worry, I know what I'm doing."

After discussing their plan, the two went back to their rooms to rest. Xu Yuehuai lay in bed, her mind replaying everything that had happened that day. She knew that this incident was far more complicated than she had imagined. But she also firmly believed that as long as she joined forces with the Ghost Doctor, nothing could stop them from uncovering the truth.

The next morning, Xu Yuehuai arranged for several of her men to secretly monitor Song Luo, as planned. She herself remained at Zuixianlou, recuperating while awaiting news. Time flew by, and evening arrived in the blink of an eye.

Xu Yuehuai's subordinates hurriedly returned and reported to her: "Your Highness, Song Luo has stayed in her residence all day and has not gone out. But strangely, there are several times more guards at her residence than usual, and they are all unfamiliar faces."

Xu Yuehuai frowned: "A new face? Could it be a highly skilled person she brought in from outside?"

The subordinate replied, "That's true. Moreover, we also discovered some unusual goods being transported into her residence."

"Goods? What kind of goods?" Xu Yuehuai pressed.

The subordinate shook his head: "We don't know. The goods were all covered with black cloth, making them look very mysterious."

Xu Yuehuai's heart skipped a beat: "Could it be related to counterfeit medicine?"

After a moment of contemplation, she instructed her subordinates, "Continue to have people monitor her, and report to me immediately if you discover anything unusual."

Her subordinate obeyed and left, while Xu Yuehuai fell into deep thought. She understood that the matter was becoming increasingly complicated. She had to act quickly to prevent the situation from deteriorating further.

Just then, the Ghost Doctor entered the room. Seeing Xu Yuehuai deep in thought, he asked, "Have you made any new discoveries?"

Xu Yuehuai looked up at the Ghost Doctor: "Yes. I just received news that although Song Luo hasn't left the manor, the number of guards around her residence has increased..."

Upon hearing this, the Ghost Doctor frowned deeply: "This is indeed somewhat unusual. Do you think these goods might be related to the counterfeit medicine sold by Li the Cripple?"

Xu Yuehua pondered for a moment and said, "It's very possible. I think the Four Kingdoms Slaughter seems to have already gotten involved."

"In that case, I must personally go to Song Luo's residence to see if I can find any clues," the Ghost Doctor said coldly.

“That’s exactly what I was thinking too. You wait here for news, and I’ll go secretly. Others can meet me when the time comes,” Xu Yuehuai said.

Seeing her resolute attitude, the Ghost Doctor stopped trying to dissuade her. He knew Xu Yuehuai's character well; once she made up her mind, she wouldn't easily change it. He could only silently pray for her safe return.

That night, Xu Yuehuai changed into a black night outfit and quietly left Zuixianlou.

Following her subordinates' instructions, she arrived at Song Luo's residence. The residence was brightly lit and heavily guarded.

Xu Yuehuai did not act rashly, but first observed from the shadows for a while. She noticed that there were relatively few guards at the back gate of the mansion, and servants were coming and going from time to time. So, she decided to sneak into the mansion through the back gate.

She carefully avoided the guards' gaze and reached the back door. She gently pushed it open a crack and found it empty. She quickly slipped inside and slammed the door shut. She knew she was now in danger and had to remain constantly vigilant.

She then walked along the corridor and came to a secluded courtyard.

There was a small building in the courtyard, with its doors and windows tightly closed, looking very mysterious.

Xu Yuehuai's heart stirred, and she decided to go up and take a look.

She quietly approached the small building, gently pushed open the window, and jumped inside. The room was filled with various medicinal herbs and bottles, and a strong medicinal aroma filled the air. Xu Yuehuai was delighted; it seemed she had found the right place.

She began to search the room carefully, hoping to find some useful clues.

However, after searching around, she found nothing unusual.

She couldn't help but feel a little disappointed. Had she guessed wrong?

"Da da da..."

Just then, she suddenly heard footsteps outside the door. Startled, she quickly hid in a dark corner.

A servant pushed open the door and came in, carrying a basket. He walked to a table, put down the basket, and began to busy himself.

Xu Yuehuai's heart stirred, and she decided to take the opportunity to eavesdrop on their conversation. She quietly approached a screen near the table and hid behind it, then pricked up her ears to listen carefully.

The servant whispered, "This batch of medicinal herbs must be handled with utmost care. Miss spent a fortune to bring them from out of town. If we damage them, we might lose our heads." His words carried a hint of mystery and tension.

Xu Yuehuai overheard another servant's whisper: "Indeed, this batch of medicinal herbs seems to be prepared for some kind of mysterious potion. Miss is extremely concerned about this, so we must be careful."

Xu Yuehuai's heart tightened, and a sharp glint flashed in her eyes: "Mysterious potion? Could it be that this is the formula for that fake drug?" A surge of excitement welled up in her heart, and she resolved to continue eavesdropping.