"Hello freshmen. My surname is Xia Mingshang, and I am a visiting professor in the Department of Life Engineering at our university. This afternoon, it is my pleasure to give you a lecture on biochemistry. Before I begin, I would like to ask, has anyone ever been exposed to this subject?"

In the back row of the lecture hall, a boy's voice came: "Teacher, I cleared all 'Resident Evil', does this count?"

On the podium, the elegant man wearing black-rimmed glasses and a smooth and straight suit did not have the slightest annoyance, and laughed: "Of course, if you can write the chemical equation of the T-virus......

Turning around and writing the words 'virus', 'bacteria', 'parasite' and other words on the blackboard, Xia Shang turned back to the students and said, "Let's talk about the theme of biochemical games that this classmate said, let's look at the common terms in these biochemical weapons, isn't it scary? But the reality is that a considerable number of these creatures not only do not harm the human body, but can actually benefit the human body." For example, the phage of a virus, unlike antibiotics that attack bacteria arbitrarily, can attack specific pathogens, and parasites, although their presence is not necessary for a healthy body, can play a key role in some specific diseases. ”

Another boy raised his hand and asked, "Teacher, is it possible that the superpowers that appear because of viruses or bacteria in movies and novels are real?"

It didn't seem that he expected someone to ask such a question, Xia Shang lowered his head and thought about it, then drew a two-dimensional coordinate axis on the blackboard, and while drawing a curve similar to "downhill" with chalk on the coordinates, he said to the students in the audience: "The X axis is time, and the Y axis is quantity. Throughout human history, the number and types of microorganisms or xenobiotics such as viruses, bacteria, and parasites have been declining with the progress of medicine, changes in the human body, and the decline of species. One study shows that by 2070, 30 percent of existing parasites are expected to disappear. So, let's make an interesting hypothesis. Dating back a thousand years, when the history of biological species was more complete, such as the early European Middle Ages, there may have been many times more types of microorganisms and xenobiotics than in modern societies. From a probabilistic point of view, there is a high probability that there will be a biological ...... that alter bodily functions."

Xia Shang thoughtfully tapped the podium with chalk and continued: "If biochemical technology had reached today's level at that time, it would have been possible to change the trajectory of history under the intentional drive of ambitious people...... Let's gossip without further ado, and get straight to the main topic of the lecture. First of all, I'm going to talk about proteins and nucleic acids......"

The moon is in the middle of the moon, and the night is like water.

Anxi Road, in front of "Suyuan Hotel".

As soon as a meal ended, Xia Shang smiled and refused his friends' invitation to renew the stall, abandoned the car, and planned to walk to the school's biology laboratory to see the strains in the petri dish.

Walking down the deserted streets, he sighed softly.

The night breeze blew, the stomach churned and the sea fell, Xia Shang stumbled under his feet, sat down on the road and bent over and retched.

Raise your head again.

A blinding light, a sharp braking.

The sharp pain was like ink dripping into the water, soaking through the chest.

The shrill honking of ambulances, the shouts of people next to them, the ticking of machines as they turn.

Xia Shang's consciousness gradually detached from his body.

——————————————

I don't know how long it took, Xia Shang woke up from his sleepiness.

His eyelids twitched, his eyes opened slightly, the things in his vision were blurred, and everything in front of him seemed to be covered with a thin veil.

Blinking vigorously, his vision finally became a little clearer.

On the humble wooden table stood a flickering candle with a simple windshield, covered with wheat stalks, with his face facing the dark roof, and a faint smell of rotting meat in his nose.

Where is the hospital?

Puzzled, Xia Shang lay flat and tried to take a deep breath, but he didn't expect that a foreign object in his mouth suddenly fell into his trachea and got stuck in the middle of his throat.

Breathing suddenly became extremely difficult, and he writhed in pain on the haystack, desperately pushing his fingers into his throat, but he couldn't reach it.

The lack of oxygen for a long time made Xia Shang's brain tingle, but it made his thinking slowly begin to clear.

Is there any way to get this thing out of your throat?!

Sea...... Heimlich maneuver!

One rolled over and fell to the ground, and Xia Shang crawled to the wooden table. Kneeling at the table with all his strength, he pressed the hard corner of the wooden table above his navel, clenched one hand into a fist between the wooden table and his skin, and pushed the other hand towards the upper part of his chest.

Once.

Twice.

Three times.

The air in his chest rushed towards his mouth, and with a violent cough, a black semi-solid object the size of a baby's fist spat out of his mouth.

After going around from the ghost gate and finally returning to the world, Xia Shang calmed his breath and looked at the black foreign object on the table through the faint light of the candle. The black, jelly-like object smells pungent of herbs.

Soon, in the candlelight, looking at his young and thin hands, he discovered an even more shocking fact.

The original 28-year-old mature man's body has actually become a teenager! plus a medieval dress in a coarse linen corset, and a wooden cross on his chest.

Crossed?

Crossed the ......

Covering his face with his hands in distress, Xia Shang pulled his hair hard.

Although I have seen similar plots in fiction movies, when it really happens to me, the first thing that comes to mind is helplessness and despair.

It took a few minutes to calm down, and the mentality cultivated by long-term scientific research work made him gradually regain his composure.

First of all, there are three things to be clear.

Who am I?!

Where am I?!

What happened?!

Hold up the candle on the wooden table and look around.

A small enclosed room, a small window under the roof, and a wooden door to the outer room. The room contained a wooden table, a stack of wheat stalks, a small pile of coal, and a stone stove that looked like a wood-fired stove for heating, with the stove's chimney branching into two ends, one through the roof and the other through the wall to the next room.

Xia Shang tried to push the door with both hands, but the wooden door did not move, squatted down to see, and a strong iron pin locked the door from the outside.

Reluctantly turned back, his eyes were fixed on the high window, he pulled the wooden table under the window, stepped on the table and climbed up, and then stood on tiptoe, his forehead barely reaching the window. Pushing open the baffle covered with thick animal skins, looking out, the violent wind and snow invaded the outside world into a white expanse, and the distant scenery and boundaries could not be seen, and only the whistling and violent wind could be heard in the ears.

Comparing the size of the window with his hand, and then looking at the width of his shoulders, Xia Shang quickly gave up the idea of escaping from the window. Besides, in such a big snowstorm, even if you can't walk a few steps outdoors, people will be frozen into popsicles.

Closing the window, he tightened his burlap robe and began to think of other ways to escape......

Just then, there was a heavy turnstile sound in the next room.

A bitter frost and snow ran down the floor, through the crack under the wooden door, into the small room.

Xia Shang unconsciously shivered deeply and shrank his body back.

Someone lit the candle in the next room, and a faint light slowly reflected through the crack in the door.

A sharply nasal voice sounded.

"Damn blizzard!"

Another hoarse voice that sounded like a blunt knife scraping through glass followed, "Huggins is late." ”

Xia Shang held his breath and listened intently to the conversation between the two in the outhouse. He was a little surprised that he could understand the meaning of the language he had never heard before.

"This kind of weather! It would be strange if he showed up on time!"

The shrill voice was full of disdain for Huggins, and he threw his snow-soaked coat to the ground.

Carefully crawling to the door and aiming his eyes at the gap in the door panel, Xia Shang squinted his eyes and observed the movement in the next room.

Under the light of the flickering candle, a bearded man's face was facing the direction of the door, and a pair of leopard eyes embedded deep in the eye sockets met the young man's gaze.

The blood in the veins seemed to have coagulated, and the frightened Xia Shang covered his nose and mouth with his hands, trying his best not to make any noise.

The leopard-eyed man stared at the door panel for a long time, and finally shifted his gaze, looked at his hunchbacked companion beside him, slid his thumb to the room where Xia Shang was, and the hoarse voice sounded again: "The one inside, what should I do?"

The hunchback untied the noose and dagger hanging from his waist, looked in the direction, and smashed his mouth: "Poor little Todd, he also gave me a bracelet made of bell flowers......"

"Put away your useless face, isn't it you the one who poured poison into his mouth just now?"

Hearing Leopard Eye's merciless accusation, the hunchback shrugged his shoulders and said in a tone of no concern at all: "Then there is no way, who told him to see something that should not be seen." ”

"Tomorrow morning, we'll have to dispose of that body!"

"I know, I know, as it always always is. Put it in a sack and throw it into the pit......"

"Don't forget the finishing touch!"

"Oh my God, you're so long-winded! Ripping off clothes, chopping up faces, burning hair, I don't need to be reminded of these tasks, I'm not a novice! I've been working all night, can you let me sleep for a while?!

The leopard-eyed man muttered a few words and blew out the candle.

The darkness gradually fell silent, and in the cramped hut, only two voices remained.

The snoring of extrajudicial murderers, the heartbeat of lambs to be slaughtered.