"Watch out for your step." Detective Tang said to her, and his voice echoed in the dark tunnel, which led downward.

According to Detective Tang, this place was initially used as a basement but later used by his friend as his laboratory and living space.

"En." Li Caiyi hummed obediently. She could barely see her own hand, which was holding the edge of his sleeve, so she had no choice but to trudge blindly.

They went down the stairs in silence. The air was humid, and there was a weird smell, like a mixture of rusty iron and dust. One couldn't help but feel suffocated when they were down here.

The path was so narrow that it only allowed one person to go through. People had to walk in line to go in and out.

Li Caiyi couldn't believe someone could really live down there. Even if she was paid, she would never agree to spend a night here.

Sensing her apprehension, Detective Tang lightly tapped her hand. "We are almost there. Hang in there."

Li Caiyi nodded, too busy with her thoughts to remember that Detective Tang wouldn't be able to see it. The latter took her silence as confirmation and walked deeper.

After what felt like forever, they finally stopped. Li Caiyi peeked from behind Detective Tang and saw there was a door at the end of the tunnel. Light leaked from the door's gap, and she felt more at ease now that it wasn't so dark.

Detective Tang knocked on the door several times, forming some sound pattern. Was it a knocking signal? Some kind of password? She saw it often in TV dramas.

Not long after that, there was a shadow of a person moving beyond the door. Li Caiyi could tell by how the light under the door was obstructed, and she gulped nervously. In the next second, the door opened wide.

Her eyes began to get accustomed to the dark, so the light from beyond the door was extremely blinding to her. She had to blink her eyes a few times to re-adjust herself before seeing the man standing at the door. He stood with his back facing the light, so she couldn't see his face clearly.

"Kong, I'm here with that person I told you last time."

The man named Kong leaned his body to the side slightly and gave a low hum of acknowledgement before he walked back inside.

Detective Tang smiled at her before saying, "He is a reticent person, so don't take it to heart if he is unresponsive sometimes."

"I understand." Li Caiyi replied, feeling lighter than before.

They entered the room, and Li Caiyi had to say that the place was surprisingly bright and clean. The first room they entered was a small living room with a couch and a table. Stacks of documents were organised neatly on top of the table.

On the other side of the room was a glass board with many unrecognisable scribbles written on it. A picture was attached to some part of it. Someone poured all his effort into research and summarised the result neatly into words and charts.

There were also bookshelves almost as high as the ceiling lined up on nearly every side of the wall.

Detective Tang went deeper, and she stepped into what seemed like a small laboratory.historical

Li Caiyi didn't know what to expect from the underground laboratory, but she certainly thought it would be darker and more sinister than this.

There was no dissecting table or row of questionable machines. There was only a wide table with many tools she often saw in the school laboratory, like a microscope or a row of flasks.

A cupboard filled with many bottles used for experiments was placed on the wall above the table.

It looked as normal as a laboratory could. Perhaps she should stop watching too many movies.

"Young Miss. Here." Detective Tang motioned her to come over, and she quickly stopped looking around.

The basement was quite spacious, and Li Caiyi ended up in a room which seemed to be a multipurpose room. There was a sink with a lot of empty flasks on it. There was also a desk with a computer, a bed, a wardrobe, and a small door, which she assumed led to a bathroom.

Detective Tang pulled a chair for her and told her to sit down while he sat on the bed. Meanwhile, the man named Kong seemed busy washing the flask without caring about their presence.

Now that they were in a bright room, Li Caiyi could finally see Kong clearly.

He looked like he was in his late 20s or early 30s. He had thick and curly hair, which almost covered his eyes. His figure was thin and looked small at a glance. However, if you looked closely, his body was pretty tall. If it weren't for his hunched back, he would probably be the same height as Detective Tang.

Kong hadn't said a word ever since they arrived here. It made Li Caiyi worried about whether they had intruded in his space and made him uncomfortable.

"Uhm, nice to meet you. My name is Li Caiyi. What should I call you?" Li Caiyi asked politely, trying to make her voice as soft as possible so as not to scare him.

However, instead of answering, Kong continued what he was doing. He meticulously cleaned the flask with frightening obsession. Even after a minute had passed, he still hadn't finished brushing one flask.

Li Caiyi glanced at Detective Tang helplessly, asking for help.

The latter sighed. "Kong, you can stop what you are doing and talk to us first." Detective Tang said, knowing that the young man probably would keep ignoring them if he let him.

"You have a guest. Rather than doing that, shouldn't you at least serve her a cup of coffee?"

"No, that's unnecessary." Li Caiyi quickly interjected, but Kong had put down his flask and rushed to his laboratory.

A few minutes later, he returned with two cups of hot coffee. He gave one to Detective Tang and put the other on the desk near Li Caiyi's chair. Then he sat beside Detective Tang and stayed as silent as a rock.

Li Caiyi didn't know what to think about this person. Well, at least he looked harmless, just like Detective Tang said.

"Young miss, this is my friend Chu Kong. He is 5 years younger than me and the one who is an expert at researching medicine, just like I told you last time. You can call him Big Brother Chu if you want."

Chu Kong clearly didn't like the idea because he immediately raised his head, which was very still up to a moment ago.

"How about if I call you Mr. Chu instead?" Li Caiyi asked carefully, and this time, Chu Kong returned to his previous posture, still refusing to say anything.

Apparently, silence meant affirmation for him.

Talking seemed not to be Chu Kong's favourite activity. Li Caiyi could only guess what he was thinking from the small reaction or gesture he made. It was tedious to do one-way communication like this, but at least Chu Kong was more tolerable than Li Junjie.

"Then, Mr. Chu, can I ask you what kind of favour you want to ask from me?"

Chu Kong: "...."

Instead of answering, Chu Kong shifted his gaze from the floor to Detective Tang on his side. As though he could read his mind, Detective Tang smiled and answered for him like his avatar.

"The reason we need you here is simple. We need you to spill some blood for us."