"You know the Mawangdui Tombs, right?"

Lighting a cigarette again, Fatty Huo began to talk to Chen Xian about the "key". At the same time, they also returned to the dean's room again, looking for the next way in this vacant room that was burnt to ruins. The secret corridor that Hong Jin-hee mentioned.

"Mawangdui in Changsha?" Chen Xian thought about it and asked, "Is it the tomb group where the uncorrupted female corpse was unearthed?"

Fatty Huo nodded, wandered around the room, and continued to talk to Chen Xian.

"In 1972, five keys were unearthed in Mawangdui. From a certain point of view, they exceeded the concept of ancient cultural relics by modern people, and were more like a high-tech product."

Hearing this, Chen Xian's interest suddenly became stronger, and his eyes became more and more curious.

"Why is it so high-tech?"

"You'll know when you listen."

After the five keys were unearthed that year, the superiors quickly paid attention to them, and laid down strict protection measures, requiring all departments to cooperate fully, and to send the five keys to the capital headquarters as quickly as possible.

But no one thought that there would be accidents under such strict protection.

On the way, no one could touch the safe where the keys were stored. There were dozens of armed guards guarding it. Eight surveillance video cameras, which were turned on 24 hours a day, were placed on the top, bottom, left, and right sides to ensure the safety of the five keys.

It can be said that in that era, being able to be protected like this was considered the ultimate.

But when the transport vehicle arrived at the headquarters and research institute, the experts opened the box and took a look...

Only four of the five keys remain, and one of them has disappeared.

"No one knows where the key went, or how it was lost." Fatty Huo seemed to recall the chaos of the year, and shook his head, "Our department is also in chaos, and the superiors are ordered to die. We started a thorough investigation, first investigating the people inside us, and then checking other people, but in the end, no clues were found."

"It wasn't until the late 1990s when the surveillance video of Hong Jinxi's theft of the Lin family's treasury came to light that we found out that the key was on him."

"He stole the key back then?" Chen Xian asked curiously.

"It shouldn't be, the time is not right." Fatty Huo shook his head and said, "We also wondered why the key was in his hands, but now that Hong Jinxi is dead, this clue is broken."

After that, Fatty Huo took a breath and continued talking with a subtle expression.

"After expert appraisal, these keys have little to do with the Mawangdui Han Tomb, and they are not products of the Han Dynasty. They can be traced back to a long time ago, even more than the Xia Dynasty in BC, and the engraved fonts on the keys have never been seen before. More complex and harder to decipher than Oracle."

Chen Xian listened with great interest and motioned Fatty Huo to continue talking.

"Of course, no matter how ancient objects are considered cultural relics, the reason why I say that they are beyond the concept of cultural relics by modern people is because of their characteristics."

"What characteristics?" Chen Xian asked.

A strange look flashed in Fatty Huo's eyes, his tone became a little complicated, and he replied in a low voice.

"unlock."

Yes, the most incredible ability of these ancient keys is to open a lock.

Electronic, mechanical, digital, cryptographic.

No matter what kind of lock, these "keys" from ancient times can be opened, and the way of unlocking is strange, which is beyond the imagination of ordinary people.

"Those keys seem to be more intelligent and can identify all locks. As long as it is leaned against the unlocked position, a lot of powder will flow out from the top of the key and forcefully penetrate the inside of the lock, and the color looks like lead powder."

Fatty Huo had seen the other four keys, so when he said these words, there was a hint of surprise in his eyes.

"The powder flowing out of the key is relatively thick at first, and the powder behind is very fine, and in the end, it is directly invisible, at least invisible to the naked eye."

"So...the key is unlocked by those powders?" Chen Xian asked thoughtfully.

"Yes." Fatty Huo nodded.

"Any kind of lock can be opened, this is the master key." Chen Xian smiled. He probably understood the superior's eagerness to find the key.

Not to mention how useful they can get the key back, it can be seen from Hong Jinxi's incident that they can't stand the consequences of letting the key go to the people.

Who has this key, and a little bit of anti-reconnaissance awareness, wouldn't it become a thief?

"I've said everything that should be said or not. You have to be strict with your mouth. Don't talk nonsense outside. The key thing is considered a secret in our department, and it will be troublesome to say it out." Fatty Huo warned.

"I know." Chen Xian nodded with a smile.

After satisfying Chen Xian's curiosity, Fatty Huo slowly became anxious.

Because after wandering around in the dean's room for a dozen times, he still couldn't find the entrance to the secret corridor.

Fatty Huo was smoking a cigarette, his brain was running fast, and he recalled the scenes of Hong Jinxi's interrogation.

Didn't he say there was a corridor here? Why can't I find it? Could it be that he lied to me?

"Which year do you have to find this motherfucker!" Fatty Huo was a little anxious, he threw the cigarette butt in his hand and stomped on the ground, "It really doesn't work, I'll ask someone to find the floor plan, and I'll just do it. I can't believe it..."

"Are you sure there is a corridor here?" Chen Xian asked.

Fatty Huo had told him about that corridor before, but he couldn't find it after searching for a long time, and Chen Xian also felt a headache.

"Anyway, that's what Hong Jinxi said." Fatty Huo frowned, his expression very distressed.

Chen Xian nodded, and silently began to walk around the corner of the wall, knocking on the wall with his hands as he walked.

According to the building construction of the mental hospital, it should be a conventional frame structure. Except for some non-load-bearing walls, the rest of the walls should be solid concrete walls.

The dean's room is located inside the corridor, and the non-load-bearing walls on the left and right sides make the percussion sound clearer, while the sound feedback from the front and rear walls is much duller.

Under Chen Xian's patient tapping, he gradually heard a different voice.

"boom."

This sound is very clear.

There is a slight echo, and it can be heard that it is hollow inside.

"Is it in the wall?"

Chen Xian looked at the wall with some doubts, and Fatty Huo hurriedly came over and knocked on the wall a few times with his hands.

"Here... it should be right!"

Fatty Huo also breathed a sigh of relief, a rare smile appeared on his heavy face, and he pushed the gold wire glasses on the bridge of his nose.

"Hong Jinxi said that the corridor is at the back of the dean's room. This location is facing the door of the dean's room. If you can meet the number, let's... eh?"

Fatty Huo was stunned for a moment, looked at Chen Xian who was doing leg presses, and asked in confusion, "What are you doing?"

"Open the door, we can't go in through the wall, can we?"

Chen Xian smiled, continued to press his legs a few times, and then slowly stood up.

Chen Xian is still very confident in his own strength. In his opinion, it is not a problem to kick open such a hollow wall.

Before Fatty Huo could stop him, Chen Xian had already jumped up, kicking the wall with great force, making a loud bang.

In an instant, the wall caved in.

Judging from the big hole that Chen Xian kicked out, it was indeed hollow inside.

"Sure enough, it's inside! We're really not wrong!" Fatty Huo saw the metal door frame inside through the gap in the pit, and he was relieved.

It seems that Hong Jinxi didn't lie, this is indeed the entrance of that corridor, as long as you pass through this metal door, and then through the corridor behind the door, you can finally reach the most secret patio space.

"The corridor you said is behind this door?" Chen Xian asked.

"Yes, you will see it when the door is opened."

After Fatty Huo finished speaking, he leaned over to the hole in the wall again and looked inside carefully.

The outer wall is only as thin as a brick, no wonder Chen Xian can kick it through, and the door inside has a gap of nearly 20 centimeters from the wall...

Why did they hide this door in the wall?

Is it possible that every time you go in, you have to chisel the wall?

Don't they find it troublesome?

When Fatty Huo thought of this, he was even more puzzled, but at this moment, he heard a strange sound.

The sound was loud and dull, and it came from that door.

It sounds a lot like some kind of gasping sound, and judging by the sound...

There was more than one person gasping for breath.