The Last Mr. Dongguo

Time ticked by, each second like a hammer blow, pounding against the gates of death. Fei Li and Li Mengying had searched the entire secret room at least ten times, but still found no clues to escape. The combination lock above their heads sat there silently, seemingly mocking yet also anticipating something.

Water droplets kept sliding down the walls, and the temperature in the sealed room was getting lower and lower. Li Mengying put her hands to her mouth, breathing warm air on them.

"What should we do? Fei Li, I feel so cold. It looks like it's going to freeze over soon, and this place will turn into an icebox."

Fei Li took off her coat and draped it over Li Mengying's shoulders. "Take care of your breathing and conserve your energy. We'll definitely get out of here."

"I don't want it. You weren't wearing much anyway." Li Mengying took off her coat again and handed it back to Fei Li. "We're both going out. If you freeze, I can't carry you."

"Alright, stop arguing. I'm not afraid of the cold. Don't forget, I can get through winter in just a shirt. I can handle this little bit of cold. Unlike you, who's afraid of the cold." The coat was back on Li Mengying's body, and this time she felt the long-lost warmth.

"Actually, I wanted to give you the coat that night, but Cheng Luan beat me to it."

Fei Li, a little jealous, made a joke. For the first time, their eyes locked on each other, and their gazes spoke volumes. What the other was thinking was revealed through their eyes.

"Then why didn't you give it to me back then?" Li Mengying's cheeks burned as she awaited Fei Li's answer.

"I..." Fei Li's shy and introverted nature resurfaced, and the words that were on the tip of her tongue remained unspoken. She simply stared blankly at Li Mengying. It seemed that at this moment, the place they were in was not some terrifying secret room, but rather a corner where the two of them could confide in each other from the depths of their hearts.

"It's changed, it's changed..." Fei Li suddenly became serious, staring intently at what was behind Li Mengying, and involuntarily uttered words that were hard to understand.

"What has changed?"

"The wall behind you is a Vigenère cipher diagram."

Li Mengying turned around to look, and sure enough, after being soaked in water, the originally smooth and blank wall now had a huge table, filled with dense English letters.

"What does this mean?"

"The Wiegner cipher is a very classic cipher. It consists of 26 letters of the English alphabet arranged in different ways. It includes 26 rows of letters, each row being obtained by shifting one position to the left of the previous row. Which row of letters is used for encoding is based on the key and is constantly changing during the process. For example, assuming the key is ABCDEF and the plaintext is CRYPTO, then the ciphertext can be obtained from this table as CSASXT. I think the password on that lock should be hidden in this table. As long as you know the key and the plaintext, you can crack the cipher."

"Where are the key and the plaintext?"

"Perhaps with Death."

"grim Reaper?"

"From Roman numerals VIII to VII we see the Vigenère cipher; perhaps the answer will be found in our future deaths."

Life and death hang in the balance.

A sense of gloom and terror hung over the secret room.

The body had already been taken away by Zou Wen, leaving behind a crime scene full of suspicious points. Bai Xin closed his eyes and thought, all the details flashing through his mind. What was the blood-stained crime scene trying to cover up? The victim was first burned and then beheaded, what was the killer's purpose? An acquaintance came to visit in the middle of the night, carrying a murder weapon, knowing the danger, why did the victim face it calmly? What did the two talk about? Bai Xin looked at the busy Han Zhen and tiptoed towards him.

"Any discoveries?"

"Captain White, the crime scene is extremely similar to one from ten years ago, but this time it's even more terrifying!"

"Ring, ring..." Xiao Li hesitated before pressing the doorbell for apartment 602. Unexpectedly, the door opened.

"Please come in!" A thin old man ushered Xiao Li into the house. "Please close the door behind you. Although it's hot, I'm afraid of the cold." The old man walked with difficulty, took a teacup from the cabinet, and poured Xiao Li a cup of hot water. "People these days are all too busy with work, only concerned with profit, devoid of human warmth. I really wish we could go back to the old days, living with neighbors for decades; the bond was incomparable. It's a pity those days are gone forever. Are you a policeman?"

"Yes." The old man's calm and composed demeanor made Xiao Li realize that he had pressed the right doorbell.

"Actually, I'm not very familiar with the person across the hall. I've only seen them occasionally in the hallway. That person leaves early and comes home late every day, so we basically never run into each other. I heard from others that he's a professor. Sigh, busy, everyone's busy..." The old man slowly sat down on the sofa, his gaze level with Xiao Li's.

"Did you hear anything unusual last night?"

"Nothing unusual, except that three people came to see him last night."

Blood is like an orphan separated from its mother's body. Once it flows out of the body, it loses its original vitality. Without the protection of the mother, the orphan can only die among all things, corroded by the air, washed away by the flowing water, and finally dispersed into tiny particles, gradually losing its original color and permanently solidifying in its last place, slowly turning from red to black.

"Captain Bai, look!" Han Zhen led Bai Xin to the bathroom and the first thing he saw was a very conspicuous basin of light red blood. Han Zhen was not interested in the blood, but instead opened the cabinet on the wall, and a poem written in blood appeared in front of Bai Xin.

"Since ancient times, all things have perished; who has ever been the first to attain immortality?"

Immortal and ageless, living ten thousand years as usual.

Red Spring gives me water, Yuanqiu provides me with enough food.

"He roams with the three celestial bodies; how could his longevity be short!"

"This is a poem by Tao Yuanming. The poem describes the author's thoughts on reading the *Classic of Mountains and Seas*. There are thirteen poems in total, and this is the eighth. Judging from the content of the poem, it's clear that they've returned!" Han Zhen looked at Bai Xin, who had a serious expression, and continued, "Based on the situation at the scene, we can determine that the living room was the primary crime scene. After killing the victim in the living room, the murderer took the victim's head to the bathroom. He first placed the head in a basin, then calmly took a hot shower. Afterward, he washed away the bloodstains on the head with the shower water, carefully cleaned up the traces he left at the scene, and then left with the head."

Calm, collected, a professional killer.

This is Bai Xin's assessment of the murderer.

The two were deeply affected by the clues found at the scene. The initial investigation had already filled Bai Xin with a strange mix of tension and excitement. After ten years of silence, they had returned. Did this mean there was a chance to solve the case from ten years ago, or would more people be taken by the murderer? What was the truth of what happened ten years ago? Bai Xin silently made up his mind that this time he would personally bring the murderer to justice.

"Captain Bai," Dongfang Lin interrupted Bai Xin's train of thought upon her return, "I've found a suspicious video."