A bizarre and terrifying experience; I messed up the dungeon world.

Before me was a huge laboratory.

No, calling it a laboratory isn't quite accurate. It's more like a combination of an operating table and an altar—in the center sits a long stone table, intricately carved with patterns, and dried black liquid remains in the recesses of its surface. A dozen or so bronze mirrors hang on the surrounding walls, each concealed by a curtain.

The green light from the oil lamp illuminated the entire space in a flickering manner.

"What...what was this place used for before?" Zhao Qiang's voice came from behind, with a noticeable tremor.

Zhou Lang didn't answer; he was observing the ground. There were drag marks in the gaps between the stone bricks, stretching from the stairwell all the way to the stone table. There wasn't just one, at least seven or eight, all pointing in the same direction.

Something was being repeatedly dragged onto that table.

Han Yingying walked to the wall and noticed a row of wooden shelves below the bronze mirror, on which were placed glass jars of various sizes. She took a closer look and her expression changed drastically.

My fingers are soaking in the jar.

It's not fake. The fingernails are still there, some long and some short, with a few clearly the size of a child's.

"Stop looking," Zhou Lang said.

Han Yingying took two steps back, didn't say anything, but her throat bobbed.

Zhao Qiang didn't dare to look in that direction at all. He kept his eyes on Zhou Lang's back, following him closely like a shadow.

Zhou Lang walked around the stone table and found a hidden compartment underneath. The compartment had a lock, much more sophisticated than the one at the bottom of the stairs; it was a four-digit combination lock made of brass.

"A password is required." He crouched down to examine the lock, having no intention of forcibly breaking it. Scissors can cut a metal lock, but the internal structure of a combination lock is different; forcing it might damage what's inside.

"Where's the password?" Zhao Qiang asked.

Zhou Lang stood up and scanned the room. There weren't many places in the laboratory that could provide clues—a stone table, a bronze mirror, a glass jar, and a wall lamp.

He walked to the bronze mirror and reached out to lift the first curtain.

His reflection was not in the mirror.

Instead, a scene unfolds: a man in an old-fashioned suit stands at the manor gate, followed by a line of servants. The man smiles kindly, but his eyes are like two black holes.

At the bottom of the image is a line of small print: First owner, year of move-in - 1897.

Zhou Lang unveiled the second side.

The scene changed. The same manor, the same entrance, but the people were different. The second owner was a woman, dressed in black mourning clothes, holding an infant in her arms. The infant's face had been painted over.

Year of move-in: 1923.

The third mirror, dated 1951. The fourth mirror, dated 1967. Each bronze mirror reflects a different owner, and each owner's eyes are black holes.

Zhou Lang flipped the page all the way to the twelfth page.

In the last bronze mirror, the scene is empty. Only the manor gate is open, and a blurry human figure stands at the entrance, its face indistinct.

Year of check-in - Blank.

"Twelve mirrors, twelve owners," Zhou Lang said, "but the last one has no name, no year."

Han Yingying followed him around and pointed to a detail: "Did you notice? There's a number in the lower left corner of each mirror."

Zhou Lang turned back and checked again. She was right. Each mirror had a small number in the lower left corner, but it wasn't the year; it was a separate number—

First side: 3. Second side: 7. Third side: 1. Fourth side: 9.

后面的是5、2、8、4、6、0、3、?

The last page is also blank.

"A four-digit password," Zhao Qiang suddenly spoke up. "Do you think it could be the numbers from the first four mirrors? 3719?"

Zhou Lang glanced at him. Zhao Qiang was unusually clever for once.

He crouched down and dialed the numbers on the combination lock—3, 7, 1, 9.

It's not open.

Zhao Qiang: "...Never mind what I said."

"No, the logic is correct, but not the first four." Zhou Lang re-examined the numbers. "Twelve mirrors, twelve numbers, the last one blank. If the password is related to the last owner—"

He paused for a moment and counted again.

3、7、1、9、5、2、8、4、6、0、3、?

十一个已知数字里，0到9每个数字都出现了——等等，3出现了两次。0到9里面少了哪个？

0 is here, 1 is here, 2 is here, 3 is here, 4 is here, 5 is here, 6 is here, 7 is here, 8 is here, 9 is here.

We have them all. There's one more than 3.

The number on the last side should also be definite, but another pattern is needed.

Zhou Lang considered it from a different angle. What if it wasn't a completion, but rather a mirror in a specific location?

He looked again at the years of those stays—1897, 1923, 1951, 1967…

The number of years between each new owner is not fixed. But there is a pattern: each owner dies before the next owner moves in.

The estate has had twelve owners since 1897. Every single one of them died here.

What does this have to do with passwords?

"Brother Lang, there seems to be something carved on that wall over there." Zhao Qiang pointed to the wall directly opposite the stone table.

Zhou Lang walked over. There was some writing on the wall, mostly covered by rust and stains. He had to get closer to read it:

"Sacrifice twelve, and the gate will be forever open. The twelfth sacrifice will become the new guardian. The code is his number."

serial number.

Zhou Lang looked back at the mirrors. Each mirror represented a different owner, and each owner was a "sacrifice." The numbers in the lower left corner were not part of the code—they were serial numbers.

The number of the twelfth mirror is blank because the twelfth sacrificer has not yet been determined.

But the password is four digits. How can a number be four digits?

Unless it's not a simple serial number, but some other kind of encoding.

Zhou Lang reread the text and noticed the last line of almost illegible small print: "The name of the guard is the key."

The watchman.

Kill the butler?

No, the one who killed the butler was a ghost, not the guard. Then who is the guard?

Zhou Lang recalled a detail—when he entered this instance, the system's background introduction mentioned: "The owner of the manor has not shown up for a long time."

Master. Not butler, but master.

There were twelve masters, each a sacrificer. The last became the guardian. But the twelfth mirror is empty, indicating that the last master has not yet appeared.

Or rather, the last one is someone who is currently in the manor.

Zhou Lang's thoughts jumped around quickly. He pulled out his pay slip from his pocket—the one he'd been given when he entered the manor. Besides his name and job title, there was a string of numbers in the lower right corner, which he hadn't paid attention to before.

He unfolded it and saw: 0413.

"Look at your pay stubs," he said.

Zhao Qiang and Han Yingying each turned out theirs. Zhao Qiang's was 0207, and Han Yingying's was 0318.

These numbers look like dates.

April 13th. The day Zhou Lang entered this instance.

But the password is the guard's "name," not the date.

Zhou Lang stood there for a few seconds, and then an absurd idea suddenly popped into his head.