That day, with his silence concluding the conversation, Yi Zhe sent Xu Tangcheng to the door of his lab and only said a single line before leaving: "Give me a call if you don't feel well."

Xu Tangcheng watched him turn and walk to the other end of the corridor. In the end, he still could not find the right words to say.

When Yu An returned to the lab, he had made a full recovery and had even regained his usual refined and courteous appearance. The people in the lab didn't know the story behind the incident and everyone was concerned about his health. There were also some people who asked him about the fight. When Yu An took some things and left, a few of them had yet to disperse and were still discussing the other day's events in whispers. Xu Tangcheng sat at the side, his ears forced to catch some words here and there. Even through his earphones, hearing those words made him irritated.

He picked up his mug and got up to get water. To his surprise, he had just reached the water dispenser when he suddenly received a text from Yu An.

This was the disadvantage of smartphones—every word in the message was laid out on the screen and he didn't even have the choice not to read it.

Come to the stairs. Yi Zhe's here.

There was a humming sound from the water dispenser. Xu Tangcheng watched as the yellow indicator lit up, his mind blank. For some reason, he instantly recalled that afternoon when things had not gone smoothly and the look of Yi Zhe's tense back as he left.

The door to the stairwell was a dark red in colour, made entirely of wood. There was no small window on the door so Xu Tangcheng had no idea what the situation inside was with the door separating him. He put his hand on the handle, hesitating for a short while, then withdrew his hand and turned to enter the elevator and pressed the button for three floors above.

The building their lab was in was very tall. Everyone naturally chose to use the elevator and few people came to the stairwell. When he pushed the door open, what poured out was the musty smell of bad ventilation. Xu Tangcheng kept close to the wall the whole time as walked down three floors and also made as little noise as possible. The conversation between the two people below him was not a lively one; the stairwell remained quiet the entire time he walked down two floors. Then, very suddenly, he heard a very familiar, "I'm sorry."

His legs came to an abrupt stop. Xu Tangcheng gripped the mug in his hand tightly. He shuffled a couple of steps and looked down over the railing.

He was looking down from above and Yi Zhe also had his head lowered, so Xu Tangcheng could only see the ink-black hair at the top of his head and his spine revealed by his waist bending. He stepped back immediately after taking just one look, then leaned silently against the wall, listening to Yi Zhe slowly say words of apology. Just a few short minutes, yet Xu Tangcheng felt as though years had passed. Twice he restrained his impulse to pour the water in his mug onto the top of Yu An's head, and he also recalled the many times Yi Zhe had appeared quiet and reticent in recent days.

All of a sudden, he realised that whenever Yi Zhe was about to make a decision he thought was important, he would always keep it all to himself silently—just like in the past when he decided that he liked Xu Tangcheng, and now when he decided to forgo his dignity.

Xu Tangcheng was no longer at the age of being an edgy teen but there were times when he wondered if it was really true that kind-hearted people were more likely to be targeted by bad luck. The people who did wrong did not think that they had done wrong and had no limit to their shamelessness, yet they lived carefree lives. Meanwhile, because they didn't want to drag the people beside them into the mess and because they were unwilling to become just as malicious, the victims could only sweep all these bitter experiences into a lesson learnt and bear the brunt all on their own. After all, only kind-hearted people had weak spots. It was the weak spots that could bring them the greatest comfort but it was also the weak spots that hurt the most when injured.

When Xu Tangcheng returned to the lab, most of the people there had already gone out for dinner. The computer screen was displaying the sequence of calculations that Xu Tangcheng had most recently put in order. He looked at it for a while, then put his hands on the keyboard and continued to type two rows.

Yu An very quickly pushed the door and entered. Xu Tangcheng didn't look up but could sense that Yu An was walking towards him.

"Tangcheng."

Xu Tangcheng pretended not to have heard him but he clicked on the mouse and minimised the compiler screen.

Yu An let out a laugh. "You don't have to be on guard against me. I heard a door being opened on a higher floor just now but didn't hear any footsteps. It was you, wasn't it?"

This time, Xu Tangcheng looked up. Without much of an expression on his face, he asked. "What?"

Yu An didn't speak anymore. He stared into Xu Tangcheng's eyes for a while, then suddenly pulled a chair over and sat down beside Xu Tangcheng. With a voice audible only to the two of them, he said, "Whether or not it was you, as long as you know it, that's enough."

Perhaps Yu An was too close to him, for the first time outside of watching horror films, Xu Tangcheng experienced his blood running cold. There was clearly no strange odour in the lab—a junior had even lit a fragrant incense just now—yet Xu Tangcheng suddenly felt nauseous.

"Actually, you were right from the start. For me to have your data and all those things is completely useless." A USB drive was placed on the table. Yu An pressed down on it, pushing it towards Xu Tangcheng. "Furthermore, this thing is yours. If you want to prove it's yours, you'll surely have a way. Academic fraud, plagiarism—I know how serious those offences are. I wouldn't really put these things into my dissertation and give you something to use against me."

The last remaining junior in the lab also left. All at once, only the two of them were left in the empty room.

"And you have to believe me, Tangcheng. No matter what, I will not harm you." Yu An lifted the corners of his mouth. "I heard your teacher mention that you have a pretty good offer. How could I really cause you to be unable to graduate on time because of Yi Zhe?"

It was the first time Xu Tangcheng was hearing such pompous words. In his heart, there was an absurd feeling of having widened his horizons. He nodded calmly and asked, "So?"

"So?" Yu An seemed surprised. "What you and I understand, he doesn't understand. Do you think I should say that he's simple or that he's dumb? Plus, just look, it's been such a long time and he has only just come to apologise to me. You've been working desperately hard for so long and I see that you're already grown thinner. This one 'I'm sorry' from him is really so hard to obtain. Since a long time ago, I've never understood just how important that bizarre dignity of his is. Looking at it now, to him, it's probably no less important than you?"

"So the reason why you put on this entire show is just to compare what he thinks is more important, me or his dignity?"

"Not entirely." Yu An raised an eyebrow. "This is just a very small matter. In the future, you will realise-"

"Yu An." While shutting down the computer, Xu Tangcheng opened his mouth and spoke in a mild tone, cutting off Yu An's monologue that irritated him with every word.

"Hmm?"

"I have a friend studying medicine who's coincidentally interning at Beijing No. 6 Hospital. Even though it's none of my business what you'll turn into in the future, seeing that we have at least been labmates for a few years, if you need to, I can help you contact them. Listen to me, there's nothing shameful about having this kind of illness. You must see a doctor and not let it drag on. Otherwise, who knows what will happen in the future."

This was the first time Xu Tangcheng was speaking sarcastically right in the other person's face. For once he was being malicious and after that, he felt refreshed and relaxed, and he wanted nothing more than to shoot off a few more common insults. Meanwhile, after he realised what kind of place Beijing No. 6 Hospital was, Yu An's face immediately darkened. "You think I'm just causing trouble for no reason?"

"Whether or not you have a reason, it has nothing to do with me. Instead, I hope that you'll think carefully. There are so many people with a strong sense of dignity but why did you target us? I can guess part of the reason but you shouldn't ever admit it and also don't ever say it. My lifespan will shorten just from hearing it."

After saying that, Xu Tangcheng got up to leave. He didn't take that USB drive nor did he bother with that mug from which he had yet to drink even a single gulp of water.

After exiting the building, he found a shadowed corner and lit up a cigarette. He finished the stick without realising it, before he even savoured any kind of taste from it. He stubbed the butt out on a trash can, then took out another stick from the pack. When the sky was dark, he finally threw away the empty pack, fished out his phone and called Yi Zhe.

Unexpectedly, no one picked up on the other end. After a sufficiently long period of ringing, the call automatically cut off.

Xu Tangcheng stood there for a while and typed out a message: I'm heading home first.

But just as he was about to send it, Xu Tangcheng suddenly recalled that Yi Zhe had told him that he would be going out with his teacher today to conduct tests and would probably only be back in the early hours of the morning. Hence, he deleted the message word by word and in the end, wrote: It's nothing. I forgot that you said you won't be home for dinner today.

He headed home. The night wind seemed to be constantly trying to placate his emotions, sweeping past him with the scent of fruits, gentle and slow. Alas, Xu Tangcheng let down nature's good intentions; when he reached the entrance of the neighbourhood, the pent-up feelings accumulated over the time he spent on that half-pack of cigarettes had yet to disperse. Fortunately, his mind was more sensible than his heart when it came to daily living. Thinking of the empty fridge at home, his mind ordered him to buy a few apples from the fruit shop beside the main entrance.

The boss saw that it was a regular and immediately pointed at the two baskets at the side. "Those two just arrived this afternoon. They're good."

Xu Tangcheng smiled and picked a few apples from each basket. When it came to eating apples, his and Yi Zhe's preferences were different. Yi Zhe only ate the crisp ones while Xu Tangcheng only ate the mealy ones. Hence, they had always bought two types, usually five altogether, two mealy and three crisp.

When he reached home, Yi Zhe's reply message finally came.

I was talking with the people from the company here just now. Have you eaten?

Xu Tangcheng's stomach rumbled at just the right time, making him feel guilty. He gave a reply that did not answer the question, saying: I've reached home.

As usual, Yi Zhe persisted in asking: You didn't eat?

No…

Xu Tangcheng had just sent it when he thought for a while, then added: I'm not hungry. I bought some apples, I'll eat an apple later.

Yi Zhe very quickly rejected his plan: No, you need to eat. Are you still going to the lab later? If not, I'll order delivery for you.

Xu Tangcheng knew that Yi Zhe actually didn't have much free time when out to conduct tests. Afraid of causing him trouble, he quickly said that he would be getting delivery right away. But Yi Zhe obviously did not believe his words and very quickly sent him the screenshot of the delivery order he had made. It was from a congee stall that they usually liked to go to.

Without waiting for Xu Tangcheng's reply, Yi Zhe sent a follow-up message telling him that on his side, it would probably take until three in the morning before they could be done and that Xu Tangcheng should go to sleep first, he would return home tomorrow morning.

Xu Tangcheng frowned. He recalled that the last time Yi Zhe went out to conduct tests, afraid of disturbing Xu Tangcheng's sleep when he got back, he had stubbornly waited until seven in the morning before coming home.

Come back right away when you're done. Don't go to the lab and lie down there.

Yi Zhe didn't reply to him anymore. He had probably been dragged off to do work after ordering delivery for him.

His little boyfriend had never placed much importance on money. After taking in the delivery, Xu Tangcheng finally realised that the screenshot that person had given him just now was just half the order. Who knew what he was thinking; when ordering two different flavours of dumplings for one person, who would order two trays? Even raising a pig shouldn't be done this way. Xu Tangcheng looked at the food occupying half the table for a long while. He really couldn't eat anymore in the end. After showering, he let the side dishes and the congee cool down and stuffed them all into the fridge for the person with the large appetite.

As he toweled his hair, Xu Tangcheng picked up his phone with his other hand and went into the bedroom.

Initially he had thought that after dawdling for so long, there should be a reply from Yi Zhe but to his surprise, his phone screen was still very empty. Other than the numbers showing the time having leaped spiritedly to ten o' clock, there was no difference from just now, quiet and uninteresting.

Xu Tangcheng tossed the phone onto the bed, then rubbed his hair hard with both hands before going near the bedside cabinet near the window to look for the hairdryer.

He was usually meticulous but when it came to his own matters, he had always saved effort wherever possible. If something could be done in one minute, he wouldn't take two minutes. Hence, he turned the hairdryer right up to the highest setting and roughly tousled his hair, wanting to dry it quickly and go to sleep earlier. His gaze wandered inadvertently and he glimpsed something unfamiliar that sent him into a stupor amidst the humming of the hairdryer. It was only when that area of his scalp started to hurt because he hadn't moved his hand for a long while that he finally jolted and quickly turned it off.

The curtains in the bedroom had been changed.

They weren't like this when he got up in the morning. Then, they should have been changed today.

Judged by Xu Tangcheng's sense of aesthetics, this set of curtains was actually very ugly. The surface was a brightly gleaming silvery grey and there was even a tacky pattern of large roses. He picked up a corner of the curtains with one hand and touched the fabric, and realised that the fabric was very thick and there also seemed to be a layer of lining on the inside. Xu Tangcheng drew nearer to inspect carefully but couldn't figure out what the lining was; it just seemed very good.

There was a small lamp on the bedside table, a pink Hello Kitty. It was a free gift from the shopping center back when they bought the bed linens. Following his principles of no-wastage and being economical with their household expenses, Xu Tangcheng had forcibly placed the lamp on the bedside table. When he first did that, Yi Zhe had objected once, saying that it was too cute and clashed with their style, and that he couldn't bring himself to use it. Xu Tangcheng had looked at him and then at the pink cat. In the next second, he pulled Yi Zhe's hand and pressed it on the cat's head, then turned to ask the person staring with his eyes wide open, "Now can you bring yourself to use it?"

Xu Tangcheng switched on the lamp and held it up behind the curtain, close to the thick fabric.

As he thought, not a bit of light shone through.

Like he couldn't get enough of it, Xu Tangcheng switched off the lights in the room. In the darkness, he covered the lamp with the curtain and tried again.

Truly not even a bit of light shone through.

He pressed the switch again and again, just like when he was a kid and had gotten a toy he liked and couldn't stop playing with it, wanting nothing more than to hug it to sleep. He couldn't help wondering how Yi Zhe had chosen the curtains, how serious his face had been when he studied their light-blocking capabilities. As his thoughts carried on, he couldn't stop himself from laughing.

What nature couldn't do, Yi Zhe could.

The dining table loaded with too much concern just now had worked by half; now, looking at these curtains, the anger Xu Tangcheng had pent up inside himself finally dispersed entirely. In the past, he had always felt frustrated even before their afternoon naps because he wanted to sleep but could not fall asleep but now, he suddenly hoped that tomorrow afternoon would come faster.

Perhaps it was because his mood had gone up and down today, going through great upheavals; when he lay down and wanted to fall asleep quickly, the theater of his mind started playing scenes uncontrollably. First it was the oppressive scene in the stairwell, surfacing in his mind snapshot by snapshot, making his heart ache. Then it was the curtains that couldn't be said to be beautiful covering the windows. There seemed to be someone who knew that he was feeling bad and was single-mindedly feeding him sweet treats.

He gripped the blanket tighter and in a single movement, rolled over to Yi Zhe's side of the bed.

He had thought that this would make him settle down a bit more but unexpectedly, after switching spots, his thoughts ran wilder than ever. In his numerous thoughts, whether of reflection or of remorse, something that could be proven at this very moment suddenly popped up. Xu Tangcheng's eyes flew open and he propped himself up on his arms.

He switched on the bedroom lights and started to go through the cabinets and drawers. Finally, under the bed, he found a pile of what he was looking for.

Xu Tangcheng crouched down, stretching out his arm and tugging that item out. As he thought, other than old curtains that had been taken down, there was also a set that he had never seen before. The light-blocking capability of this set wasn't as good as the one hung up now. Xu Tangcheng flattened out a small spot and held it up against the light above his head. Even though it didn't really let light through, the entire area was still a little bright.

Like he said; with that person's spendthrift nature, how was it possible for him to be satisfied with just one purchase?

He folded up both sets of curtains, stacking them up neatly on the floor, then washed his hands and got into bed.

The things that were not good, that Yi Zhe was unwilling to have him see, he would pretend not to have seen them. But the things that were good, he would bring them to light without asking him.

At two in the morning, Yi Zhe received a message right after he left the control room. The moment he saw the contents, the moment they entered his eyes, his brows immediately furrowed deeply.

Can't sleep, waiting for you to come back.

The senior who was talking to him was shocked by his suddenly severe expression. Thinking that there was something urgent, he asked in concern.

"It's nothing." Yi Zhe shook his head. He lowered his head and sent a message in reply before asking, "How long more before it's done?"

"When Old Song's part is done, we just need to test another time and we're done." His senior took a look at the time. "It depends on whether things go smoothly for Old Song or not."

Hearing this, Yi Zhe immediately turned around and headed back in. "I'll help with the calibration."