"Xiao Ma, leave the room first and hide in the security booth." Li Yuebai raised his head from the computer and warned sternly without hesitation.

That strange figure must be a dormant vampire. The worst possible situation is that it is still in this room!

"Okay, okay..." Ma Xiaoting was too scared to approach Xu Lili's room. When she heard this, she nodded obediently, and then walked backwards step by step outside. Although she was very curious about what was on the computer, fear still overcame curiosity.

At this moment, her cell phone rang. It was the sound of the instant messaging tool.

Ma Xiaoting was startled and reflexively took out her cell phone and opened it.

It was sent by Wu He.

Wu He: Xiaoting, what is Lili doing?

Wu He: Lili sent me a photo before, which scared me to death. Then she didn’t reply to me for a long time. Have you seen her?

Wu He: [Photo]

Wu He: This is the picture. I don’t know what app she used to make it…

That horrifying photo appeared on Ma Xiaoting's mobile phone screen.

"Ah——!" Ma Xiaoting let out a crying scream, the cell phone slipped from her hand, and then she fainted on the ground.

She had worked so late, hadn't eaten dinner, and had been in a state of fear and tension. Now this photo was the last straw that broke the camel's back.

Li Yuebai lifted her up from the ground, moved her to the sofa, and covered her with a blanket. He checked her pulse and breathing, and found that she was fine, just fainted. In this situation, it might not be safe to send her out, so he could only let her stay here for the time being.

Then, he turned on all the lights in the rental house and carefully checked the house, from conspicuous places to cupboards and drawers, but found no trace of the dormant vampire.

Could it be that it has escaped?

Xu Lili's body is right here, why doesn't it possess her?

"Is Wu He suspicious?" Ye Qing asked, "If he hadn't sent the picture to Ma Xiaoting..."

"Not necessarily. I think Wu He has been very normal so far." Li Yuebai said, "If it were someone else, they would do the same thing."

Now is the age of instant messaging. If a friend suddenly sends you a scary photo and you don’t reply to your message, your first reaction is of course to ask the people you live with.

Ye Qing first opened Xu Lili's personal homepage. Since a password had been set when she turned on the computer, she logged into her personal homepage directly. There were some public diaries and private diaries on it.

Public diaries are normal, but private diaries...

It's all some strange gibberish.

This kind of rambling started on July 20, when Xu Lili published a diary entry titled: I really want to open a box. The content was a stream of consciousness, all about how much she wanted to open a box and how strong this desire was.

"Want to open a box? Is this a metaphor? Want to solve a problem, want to free myself?" Li Yuebai couldn't tell for a moment whether this diary was related to the case.

The middle school boys and girls in his class wrote this kind of stream of consciousness in their daily diaries, often saying "In this dark world, I am like a lotus stuck in the mud..."

If you take it all seriously, you'd be a fool.

On July 30, a few days ago, Xu Lili published another blog post titled: I really want a necklace. It was also a stream of consciousness, and the content was about how the necklace tempted her and how she wanted to get it at all costs, even if it cost her her life.

This feeling is easier to understand. I'm sure everyone has it. Favorite expensive jewelry, favorite game consoles, favorite mobile phones... For a girl of Xu Lili's age, having a necklace that she particularly wants is nothing new.

Unable to find any important suspicious points in the log, Li Yuebai instructed Ye Qing to open the online shopping platform, log in with the default account, and then open the "Purchased Items" list.

They were all cheap daily necessities, clothes and the like, and there was no record of any particularly expensive necklaces being purchased.

They had just searched the entire room and found several necklaces. According to Ma Xiaoting's identification, they were all cheap, ordinary brands and ordinary styles. None of them matched the tone of "loved but hard to come by" described in the diary.

Li Yuebai frowned as he looked at the list scrolling down bit by bit. His mind was filled with a myriad of thoughts, tangled like a hemp rope that couldn't be untangled.

"Okay, go slow here." Li Yuebai put one hand on the table and the other on Ye Qing's shoulder.

"Slow down?"

"Slow down the list, it's almost July 20th." Li Yuebai frowned and stared at the screen: "On July 20th, Xu Lili posted a strange blog post. Maybe it's related to what she bought."

Strangely, there was no purchase record on July 20th; she didn't buy anything that day.

"Then continue scrolling down. Maybe it was not purchased on July 20th, but received on July 20th!" Li Yuebai said.

Soon, a special "Purchased Items" message was pulled to the front.

The purchase date is July 1st, and they promised to deliver it within 20 days...

Perfect time!

Look at the description of the item again - there is no photo, only a text description: Castle Stone.

The detailed introduction is: A centuries-old country castle collapsed in the eastern suburbs of Landshut, Germany. The fallen stones were sold to tourists as souvenirs, and each stone cost only a few euros. Attached below are photos and videos of the castle before it collapsed. The scenery is really beautiful. The castle is dark black in color, not big, and simple and heavy.

Selling bricks? This is not surprising. There is a long-standing joke in the spiritual chicken soup world: when the Statue of Liberty was built, the builder was worried about what to do with the remaining waste. As a result, a smart employee proposed: process the remaining waste into small Statue of Liberty and sell them to tourists! So he made a lot of money again... Regardless of whether the joke is true or not, this business model is everywhere in modern society and is not surprising at all. Li Yuebai himself has bought souvenirs made of leftover wood from a tourist attraction.

When they were rummaging through Xu Lili's belongings, they found the only thing with a different style among a pile of miscellaneous items. It was a black, square stone. It must be the stone from the ancient castle.

The two clues can be connected, but I don't know what they are for.

After receiving the castle stone, Xu Lili posted a blog post saying: I want to open a box...

Stone, box, stone, box... From a visual perspective, there are similarities.

Could it be that the box refers to the castle stone?

Li Yuebai squatted down, dug out the stone and held it in his hand - it was not very heavy, about the same size as an ordinary brick, but half the weight. It was black basalt, rough, and there was no opening to be found.

If it was the box, did Xu Lili succeed in opening it? Did she open it and then close it again, or did she never open it?

Recalling the anxious tone in the diary, Li Yuebai guessed that Xu Lili must have opened the box, otherwise, she would not have mentioned the box again.

Can this thing really be opened? Li Yuebai and the stone stared at each other in disgust. After struggling for a long time, he couldn't find the secret. In desperation, he had to hand the stone to Ye Qing.

Ye Qing took it and weighed it: "The weight is wrong."

"It's lighter than ordinary bricks, at most one kilogram." Li Yuebai estimated.

"It weighs 983.5 grams, and the internal structure is a bit complicated." Ye Qing had a paralyzed face and tapped on the stone with his slender fingers: "There is a cavity inside. In addition to the cavity, there is also a cylindrical channel on the left side, in the shape of a T..."

Li Yuebai was confused: "Xiao Ye, do you have a built-in X-ray scanning function?"

"I can't see it. I guessed it based on the knocking sound." Ye Qing didn't even blink, making it hard to tell whether what he said was true or false.

Never mind. Since I have already traveled through time, it wouldn't be a bad thing to have a companion with special abilities.

Ye Qing took a piece of paper and roughly drew the speculated internal structure.

After finishing the painting, Li Yuebai took it and looked at it, and suddenly he realized, isn’t this a variation of the “Lu Ban Lock”?

When I was a kid, there was always this kind of toy for sale at the school gate. There were wooden and iron ones, and there were several sets. There were square, round, and strange shapes. They all used the simplest mechanical principles to put the pieces together. As long as you find the right way to disassemble them, you can take them apart. These little toys are sometimes called "Luban locks" and sometimes called "Kongming locks." Even now, you can still buy them.

There is a type of Luban lock that is a square wooden box. You cannot open it directly. You can only tilt it in a certain direction and then tilt it in another vertical direction - using gravity to transport a small heavy object inside to a certain key point before you can open it.

The situation of the castle stones is a little more complicated - there is a winding maze-like passage inside, and there is a small stone ball in the passage. The stone ball must be transported to the end of the passage before it can be opened.

"You do it." Li Yuebai decisively handed the task to Ye Qing.

Ye Qing might really have special abilities. He is particularly sensitive to numbers, calculations, weight, shapes, etc. Chinese teacher Li Yuebai feels inferior to him.

Ye Qing closed his eyes, held the stone with both hands, and turned it lightly. No matter what he did, his expression was particularly serious and focused, without any arrogance or disdain as a genius. Just like just now, no matter how simple the computer password was, he would seriously crack it, and his expression remained unchanged after successfully cracking it. He was completely different from Li Yuebai, who would show off as soon as he solved a problem.

Not long after, a low clicking sound was heard from inside the stone wall of the castle, and then it opened.

Li Yuebai had read some martial arts novels and always felt that if the mysterious box was opened, some poisonous smoke or poisonous needles might come out of it. So, he subconsciously made a sudden move, went around behind Ye Qing, covered his mouth and nose, and pulled him back.

Ye Qing was almost pulled by him and lost his balance.

Fortunately, nothing remarkable came out of the stone.

A small coffin lay quietly in the cavity inside. It was black, roughly made, and of an ancient shape. Its material could not be seen. There were several deep marks on the surface of the coffin.

At this point, Li Yuebai was certain that this thing was related to Xu Lili's death.