Perhaps because there is nothing to do at home besides sleeping, I have been dreaming about my high school days incessantly lately.

Strangely, the time I spent as a desk mate with He Lin Shi only accounted for a small part of my entire high school experience, yet in my recent dreams, she is always my desk mate. Some scenes that seemed to have happened, and some that never did, appear clearly in my dreams. After waking up, I am always unable to distinguish what is real and what is fake.

We became desk mates in the second semester of our sophomore year. Originally, at the beginning of the semester, I volunteered to move to the back row because the math teacher said that seeing me during class affected his mood. However, I don't know if it was because the head teacher felt a sense of pity for my talent, or because my mother took me to give him a bottle of Moutai during the Qingming Festival.

In any case, the third time I was late in the morning, he suddenly pulled me aside, not asking for the reason for my lateness this time. He chatted with me about my ideals and my plans for the future. He said he had always felt that I was a talent worth molding, and as long as I put my heart into it in the days to come, I would definitely be able to get into a good university. Then he had me sit in the middle of the third row, directly facing the math teacher's teacup.

To be honest, I have probably heard the words "you are a talent worth molding as long as you work hard" ten times since I was a child, but he is truly the first teacher to actually take action and put me in this hotbed for top students. That was the math class I slept the least well in since I started high school.

The bell rang for the end of class, and I just sat down. He Lin Shi gave me a thumbs up and said: "Impressive. This is the first time I've seen someone who can sleep while standing up, and even a piece of chalk couldn't wake you."

I shook my head, not yet adapted to the surrounding environment. There were people above, below, to the left, and to the right; there was no sense of security like having my back against a wall. The girl in front turned her head slightly, and her hair swept across my desk. I started to miss my old seat.

But fortunately, He Lin Shi was one of the few girls in the class whose name I knew. Unlike others who were remembered because they were pretty or had good grades—I remembered her name because of her self-introduction at the start of the semester. She said her name was supposed to be He Lin, but when her grandfather took her to register her household, the staff asked when the child was born. Her grandfather replied, "He Lin Shi [He Lin was born on]..." [referring to the date]. And so, she was named He Lin Shi. As for my name, it was always on the duty roster on the blackboard, and she surely knew it too.

It saved the trouble of introducing ourselves.

She wasn't the type of girl who liked to talk much. If it weren't for her name, I probably wouldn't have remembered that such a person existed in our class even after three years. She liked to hoard pens, liked to take notes in various colors, liked watching anime—there was a big Naruto or something I didn't recognize drawn on her pencil case—had a few friends she went to the restroom with but couldn't walk home with, liked Chinese, was bad at math... If you happen to run into a girl you don't recognize at a class reunion who greets you, and you want to ease the awkwardness of not remembering her after she tells you her name, you can say: "Oh, I remember that time the Chinese teacher read your essay in class."

He Lin Shi was just that kind of girl.

Our real interaction didn't start until a week later. When I realized that I really couldn't sleep or play on my phone in this seat, and that I really couldn't understand the math teacher's lecture, I finally turned my head toward my desk mate.

She quickly returned a puzzled look. "I'm so sleepy!!" I tried to convey the message to her with my eyes. She thought for a while, then picked up a pen and gestured with the tip toward my thigh. I quickly shook my head to wake myself up.

After class, I slumped on the desk and asked her: "Are you always this ruthless to yourself?" She: "I usually don't get sleepy during class." I: "Then why did you pick up the pen so skillfully?" She: "Because my previous desk mate used to have me do this when he was sleepy." I: "..." She: "Let me ask you a question. You didn't listen to any of the previous math classes, but you knew how to do these problems just by listening to this one. If you're so smart, why are your grades so bad?"

I lifted my head up all at once, leaned a little closer to her, and lowered my voice: "Actually, I only have three years left to live." The pen she was spinning stopped, as if she were waiting for me to continue.

"It's a heart problem. It was diagnosed when I was a child. The doctor said it's usually hard to make it to twenty. My parents, they felt that since they brought me into this world and couldn't give me a healthy body, they should let me be happy. When other kids were in kindergarten, I was taking tourist photos all over the country. Later, they realized, 'Hey, it's still early, even if I can only live to twenty, that's still more than ten years, what if we spend all the money at once?' So they sent me to school. They said that university life is also a unique experience, and it would be a pity not to experience it once in this life. I didn't believe it; neither of them went to university. But back then, I didn't really feel like I was any different from others, so I went to school just like everyone else."

She must have been captivated by my superb storytelling skills; the pen stayed on the web of her hand and never started spinning again.

"I actually don't think it's a big deal. Besides not being able to do strenuous exercise, I haven't had any problems since I was a kid. No matter what happens, my mom always says, 'As long as you're happy, it's fine.' However, after causing a few troubles, I felt bad watching them clean up after me. So I decided to live an ordinary life. Besides, I don't think I need university; I'm quite happy with my high school life."

After a moment of silence, she asked me: "Then if you didn't have this, what would you want to do in the future?"

That second half of the question was something the head teacher had asked me a while ago. At that time, I answered that I didn't know, maybe I wanted to get into university. But looking at He Lin Shi's teary eyes, I thought about it seriously and answered her: "When I was a kid, I wanted to be the owner of a hardware store, selling small gadgets. Back then, my dad would fix things and often ask me to go to the hardware store to buy this or that for him. I felt that if I opened a hardware store, I could make anything I wanted. After I grew up, I stopped thinking about that question."

She took a deep breath, and I patted her shoulder and smiled: "Don't you dare shed tears; if others see it, they'll definitely say I'm bullying you." She dodged my hand and rolled her eyes at me: "As if. Get lost."

The bell rang for class, and she quickly switched to study mode, then handed me a note: "I'll tell you a secret of mine after class too."

What was that physics class about? I've completely forgotten. I only remember the jokes the physics teacher told to wake people up during class. He said that when he came to class, it was especially hot, and he saw someone selling watermelons on the road. They were cut into pieces, and he really wanted to eat one. But at the same time, he was a man of principle, and he couldn't do something like eating while walking on the road. Just as he was about to endure it and give up, he suddenly saw a small alley nearby. So he squatted in the alley and finished a portion, and added at the end: "Ah, that was truly refreshing."

After class, I looked at He Lin Shi. She was staring at the physics book as if thinking about a problem, then turned her head and said to me: "I came from the future." I: "Pfft..." She: "Really, if you don't believe me, then I won't tell you anymore." I: "No, I just thought about the mood I was in the day my dad told me I could only live to twenty. Hahahaha, so when did you come from? Have you heard about the national football team winning the championship?" She: "No... not that far. I just have memories of living until 2020, and then one day I woke up and it was 2016 again." I: "Something like time travel?" She: "Yeah, something like that." I quickly found a pen and paper: "Then do you remember tomorrow's lottery numbers? No, wait, who remembers that stuff? Do you know the winner of this year's World Cup?" She: "..." I: "Then you don't have any evidence to prove it to me either." She: "I remember that in 2020, there was a huge epidemic in China, and I also remember that I entered university in 2017. Oh, and Naruto ended. These are all very vague memories, just like a dream, but when something impressive happens, I recall that I've experienced it once before." I: "Do you know about the Observer Theory?" She: "Hmm?" I: "It means that even if you go back to the past, you can only act as an observer. You cannot do things you didn't do before you went back, otherwise, a tiny disturbance could cause unpredictable results, eventually leading to the event of you going back to the past not happening, and a paradox is created." She: "Uh-huh?" I: "So, if someone can go back to the past, the best method is to close their eyes before going back." She: "You mean, the fact that my memories of the future are blurry is actually protecting me?" I: "Something like that. I want to ask you one thing: when you were in... 2020, did you see me?" She thought for a long time, then shook her head gently: "No... you left here in your senior year. It seems you went to university later, I have no impression."

Regarding the fact that He Lin Shi came back from the future, I actually didn't have much doubt. Although the numerous popular science books I've read all said such things were impossible, I have never been a materialist. On the contrary, I was more keen on helping her find the answer she had been puzzled about—what exactly she came to the past to do.

After all, even if God granted her wish to return to the past, she should have a reason for having to return. This often happens: you take out your phone to scroll through your feed, check Weibo, and suddenly forget what you took your phone out for in the first place. So you scroll through the feed you just scrolled, check Weibo again, and suddenly realize, 'Oh, I was going to check the time.'

Before telling me about this, what He Lin Shi was doing was exactly this. When she realized she couldn't think of why she came back no matter how hard she tried, she thought for five minutes, then put on her schoolbag and came to school. Even though for her, this road was one she had walked four years ago. She intended to repeat what she had done before, hoping she would remember what she had originally intended to do.

On the way home, I pushed my bicycle and thought about the next possibility she would deny. It was only after so long that I realized our way home was in the same direction. I suddenly looked up: "Could it be because you didn't do well on the exam? You have the impression of entering university, that school is trash, you were treated unfairly there, so you decided to go back to..."

My voice got lower and lower. After walking out of the shadow of a building, the sunset suddenly wrapped around both of us. She was walking in front, set against the afterglow, and then turned back to ask me, "What?" The shadow of the bicycle was stretched very long, and her short hair was dyed the color of the sunset.

"The timing is very important!" I analyzed for her: "Why four years ago? Because this is the time when you can solve the problem you need to solve. Think about it, after you came back, have you met anyone who left a deep impression on you, or has anything happened that left a deep impression on you?"

He Lin Shi handed me a can of Coke, then sat down next to me, looking at the setting sun just like me.

"If I have to say, does moving count?"

I perked up: "It counts! Did you lose something important when you moved? A love letter received in elementary school? The address of a good friend?"

"But, that's impossible... I just bought the upstairs and turned it into a duplex, and I didn't throw away anything from the old room."

...

"Then what else is worth going back to the past for?" "Love, it can only be love, right..."

He Lin Shi patted my head: "What are you muttering about?"

"I'm asking you, have you met that kind of boy you fell in love with at first sight since you came back?"

"No."

"Then what type of boy do you like? Should we check against the boys in our class?"

"Good-looking, good grades, loves sports, loves to laugh, has a good temper, and it would be even better if he could cook, preferably he could also..."

"Stop, stop, that's enough, basically ruled out everyone around us."

"What about you? What type do you like?"

"Emm... long hair, big breasts, good figure, fair skin..."

"Stop it, that's not liking someone, that's clearly the restless stirrings of pre-puberty."

"I actually think desire is more real than love. Desire is a normal, healthy need. When you have desire, you need a woman. After it's satisfied, you can do other things. But women are different; they label this as love and take it very seriously, and they keep trying to convince us that this is everything in life."

I have an impression of these words.

"Heard it in the future? Could it be a clue? Think hard!"

"No, it's a novel by Maugham. You talk about these things with girls? You're not even an adult yet, be careful."

The effort to find a reason lasted for a week and ended in nothing. I feel like I listed all the thoughts I would have that would make me want to go back to the past, but none of them triggered He Lin Shi's memory.

One day, while my mom was watching TV, she told me that they had talked to the head teacher and learned that it would be difficult for me to get into university with my current situation, so they decided to let me go to a boarding school during my senior year to study hard. I subconsciously wanted to refute: 'Isn't studying meant to be happy? Why be so miserable?'

But the words got stuck in my throat. I remembered what He Lin Shi told me, that I wasn't in this school during my senior year. This was what the observer saw.

My mom was still talking about why they decided this, saying that she and my dad really didn't want me to waste so many years and end up with nothing.

"Okay, I'll go."

It wasn't to avoid ending up with nothing; after all, I hadn't treated myself badly all these years. It was just that I didn't want He Lin Shi to end up with nothing because of my choice. After all, I didn't know what would happen if I made a choice different from her memory.

He Lin Shi carried her tray and sat next to me, saying: "Rare to see you eating in the cafeteria. If I remember correctly, you'll be transferring schools after the exam. Every meeting is one less."

I took a mouthful of rice and said with a thick tongue: "It's not because I want to spend more time with you. I'm still very concerned about the reason you came back. I feel like if I don't help you figure it out, I won't be at ease when I leave. It's like when you're taking a shower and you suddenly hum a line, 'At the beginning, it was you who wanted to break up, break up then break up.' But you can never remember the name of this song. And the rest of the time in the shower becomes especially hard to endure."

He Lin Shi smiled and said: "Thank you for your hard work. I remembered one more thing. Didn't I tell you before that there was a very serious disease in 2020? The time I returned to the past seems to be the day after that disease ended. Because I recalled seeing the news that the epidemic had ended."

I thought about it, this also had nothing to do with you returning to the past, but it could be considered good news. "Sigh, it's hard to endure. If you remember what you came back to do, you must tell me the first thing, the very first thing."

He Lin Shi nodded vigorously and said: "Okay!" Then she shook her head: "No, in my memory, we should have little contact after this. How about we set a time? Let's meet on the second day after the epidemic ends in 2020. At that time, I will tell you everything I did when I returned to the past."

I swallowed the rice in my mouth and saw He Lin Shi staring at me with her teary eyes again.

"Okay, it's a deal."

On the day the exam finished, He Lin Shi gave me a small pendant and said I must remember to wear it during the college entrance exam. She went to the temple to pray for "winning the laurel in the toad palace." Because I hadn't prepared anything to give her, I smiled at her a bit embarrassedly and said thank you.

This was the last time I saw He Lin Shi in high school.

The boarding school was indeed effective, and combined with my intelligence, I didn't have any worries during the college entrance exam. On the day the scores were announced, the whole family accompanied me to wait. At first, they said it would be announced at midnight, then the server crashed. Then my dad kept refreshing the webpage, and my mom was peeling oranges and chatting with me. I played with the small pendant He Lin Shi gave me and decided to take a shower.

Suddenly, a sharp pain in my heart, and I fainted on the sofa.

When I woke up, it was my dad's face. I had never seen such an expression on his face, laughing until he had crow's feet, yet his eyes were full of tears. Before I opened my eyes, I had already thought about what to use to comfort them, so they wouldn't be too sad. As a result, the current situation caught me off guard.

I looked around and asked him: "Where's Mom?" Dad said: "She was too excited and fainted, she's getting a glucose drip nearby. Don't worry, listen to me, I was so excited I almost fainted too. The doctor checked and said, your heart is very healthy!" I felt like I had heard my dad say he also came from the future: "Very healthy? How is that possible?" My dad's voice trembled as he said: "The doctor also said it's very rare, but it's not impossible for the body to heal itself. After all, your mindset has always been kept very well. However, you still need to observe for a while." He didn't intend to let me digest it, as if he had been holding it in for a long time, he quickly said: "Also, your grades are out, they are about the same as your estimated score, about twenty points higher..."

When I enrolled in September, I refused my parents' request to send me. I, who had been held in the palm of their hands since I was a child for fear that I would melt, could finally righteously tell them that I wanted to go out and try it alone. The two suitcases my mom had packed full for me three days in advance were cleared out by me until only a small bag remained.

It was sunny on the day I arrived at school, 32 degrees. A cheerful English song was playing on the campus radio, and I was the 5557th person to report that day. Walking on the road, I was thinking about whether I really wanted to open a hardware store in the future. On the way back to the dormitory after reporting, the wind brought a scent of another city, different from home. I saw He Lin Shi wearing a white dress, her long hair flowing, looking at me and smiling by the side of the road.

"Tch, she lied to me from the very beginning."