The moon was bright and the stars sparse overhead. Around them, voices hummed quietly, though in their immediate vicinity, students were seated fairly spread out — and looking across the whole field, there were still quite a few people. Everyone was quietly murmuring with their own companions. The film’s audio was loud enough to cover any other sounds.
“When I speak to people of a non-mathematical nature, they always struggle with the notion that mathematics can be beautiful…”
“I don’t know. I found a formula, I just can’t understand it.”
Amid all that ambient noise, Xie Yichen looked at her lovely eyes and said in a low voice: “My parents’ marriage is… a bit unusual.”
Ning Sui didn’t dare to hazard a guess rashly. After thinking for a moment, she asked quietly: “A marriage in name only?”
She knew there were many family enterprises where, even if the couple’s feelings had broken down, they would stay married due to shared interests and financial ties.
“A bit beyond that.” Xie Yichen gave a slight smile. “Have you heard of an open marriage?”
Ning Sui’s lashes moved suddenly.
In the moonlight, she looked at his expression without blinking.
Since the beginning of what she’d been saying, she had chosen every word with care, and now said gently: “…That means, they don’t mind the other person being with other people — is that right?”
Xie Yichen admitted it directly: “Yes.”
How to put it — described kindly, it could be called freedom and equality, the ability to freely choose intimate partners. Described plainly, it was mutual infidelity, a lack of moral boundaries.
Xie Yichen could accept their choices, but had never, deep down, truly approved.
Once, his parents’ marriage had given him the feeling of walking on thin ice — as if their family was built on nothing more than a sheet of flimsy paper, and the slightest outside force would bring it all crashing down instantly.
So asking it aloud just now, he had been somewhat afraid that Ning Sui might not be able to understand, that she would see him as something abnormal.
But she didn’t seem to react that way at all.
Ning Sui’s expression was quiet and unhurried. She lowered her gaze, looking with focus at his arm: “Then the scar is—?”
He gave a slight pull at the corner of his mouth, told her the whole story from beginning to end, then paused and added: “It wasn’t as dramatic as Zhang Yuge made it sound. I was just caught in the crossfire.”
Ning Sui connected it with all the clues from before: “So — was it in middle school that you found out about all this?”
“Mm, first year.”
Xie Yichen opened a can of beer, handed it to her first, then opened one for himself. He lifted it and drank, his throat moving as the liquid went down. His gaze stayed dark. His eyes were calm and dim, holding no particular emotion.
So that was why he had gone off on his own to rent a place and live alone.
So that was why he said his temperament back then had been bad, and he’d always been getting into fights.
Ning Sui looked at him with wide eyes, slightly stunned.
Every piece of the puzzle clicked into place in that moment. Something in her chest, that pool of salt water, grew even warmer and more achingly full — somewhere tight and sore, a feeling she couldn’t quite name.
Xie Yichen lowered his eyes, a rueful curve forming at the corner of his mouth.
His voice softened, but couldn’t quite hide the low roughness beneath: “Still frightened, aren’t you.” He thought for a moment. “It’s all in the past now. I’m—”
“Xie Yichen, stop smiling.” Ning Sui said, suddenly.
Xie Yichen’s movement paused. He seemed taken aback for a moment.
“If you’re not happy, you don’t have to smile,” she said softly. “You don’t need to be like you were as a child anymore.”
Facing unfamiliar reporters, a wall of dark camera lenses, forcing yourself to do things you didn’t want to do.
“……”
The light from the screen kept flickering and shifting. The young man’s gaze was dark and deep and fathomless, like the bottom of a still lake — obscure and fixed on her.
A light fell into his eyes. After a long moment, Xie Yichen gave a very quiet hum: “Understood.”
The words ended, but his gaze didn’t leave her even slightly.
Ning Sui was holding a half-finished beer can, and in that moment, she hadn’t had time to look away.
Both of their hands rested on the ground beside them, fingertips separated by only a few inches, but both holding still, neither moving. Only their eyes had met the other’s, and now, as if following the warm, heavy pull of the alcohol, they held each other’s gaze — something igniting at a touch, watching each other intently and unbreakably.
Ning Sui’s breathing grew involuntarily unsteady, but she couldn’t bring herself to stop looking at Xie Yichen’s eyes.
His eyes were beautiful — sharp and hawk-like, yet carrying a trace of wild, unruly energy. The long lashes, dark as ravens’ feathers, draped downward. His expression was unreadable, and Ning Sui felt an uncontrollable flutter of anxiety, as though she had been rooted in place.
Were they too close?
……She didn’t know.
She really didn’t know.
The warm, steady scent of him drifted across her face. Even the tips of her ears had grown hot. Her limbs felt as if they’d stiffened and couldn’t move.
Just as something was about to burst out of that breathless stillness, a corner of the space suddenly began to vibrate repeatedly, accompanied by a spectacularly mood-breaking ringtone: “Good luck to you, may good luck come your way—”
“……”
Ning Sui jolted as if startled awake, then — as if surfacing from a dream — began searching for her phone.
She checked her down jacket pockets first. Nothing. Then quickly unzipped the outer pocket of her bag. Also nothing.
The ringtone wasn’t particularly loud, but it still drew the attention of some nearby students, who turned to look.
Fortunately their spot was fairly secluded and everyone was seated quite far apart, so the disruption wasn’t too great.
As she searched, Ning Sui could feel the heat rising rapidly in her cheeks.
— Save me, where on earth is it? Why can I hear the sound but absolutely cannot find the thing?!
Was she blind, had she gone blind?!
Just as she was scrambling around in a panic, a slender hand plucked her phone up from a fairly conspicuous spot on the spread-out mat and held it out to her without a word.
Ning Sui: “……”
The ringtone was too disruptive — she killed the call at top speed and glanced at the screen. It was Liang Xinyue.
In WeChat, Liang Xinyue had sent a concerned message asking why she still hadn’t come back. Ning Sui gripped her phone, steadied her breathing over several slow counts, then replied: [Out with a friend.]
Only then did she notice that, without realizing it, it was already nearly half past eleven.
Fanfan had sent a message a few minutes ago asking where she was. Ning Sui replied: [At Tsinghua — a club event, watching a film. Wrapping up soon.]
Fanfan had been remarkably open-minded lately — maybe because Ning Sui had been actively sharing more of her daily life with her these past days. She was no longer as strict as before, and had even tacitly allowed Ning Sui to delete the location tracking app from her phone.
After Ning Sui replied, Fanfan came back with: [Oh, are you with someone?]
Ning Sui’s heart gave another small leap: [Yes.]
Xia Fanghui: [Okay, get back to your dorm early. Mom’s tired — going to sleep now.]
Suisuisui: [Got it, good night Mom.]
Her mom was strangely reasonable tonight — no frantic calls, just went straight to bed.
Ning Sui put away her phone. A few seconds passed before she finally lifted her head. Xie Yichen was holding his beer can, his profile turned toward the film screen, his expression looking as though it had returned to its usual composure.
The atmosphere from moments ago had also vanished without a trace. Ning Sui thought staying a while longer tonight probably didn’t matter, so she hugged her knees and settled in to watch the film properly.
Her alcohol tolerance was actually not as poor as Fanfan imagined. Having had two or three cans, her thinking was still relatively clear.
But alcohol was a curious thing — even without being drunk, it altered your perception of the world around you. Her head felt a little light, her reactions somewhat slower than usual.
In the film, the male lead Nathan had an unusual gift for mathematics. Young as he was, he represented the British team at the Mathematics Olympiad.
Ning Sui: “Xie Yichen.”
He glanced over: “Mm?”
“I heard your uncle is a professor of complex analysis at Tsinghua — so you started getting into mathematics very early?”
Xie Yichen’s tone was unhurried: “Right.”
The Purple Bamboo sports field had an artificial turf surface, dotted evenly with little rubber pellets. Ning Sui picked a few up and collected them in her palm, then let them fall back down like sand through an hourglass, watching with careful attention: “Then your uncle’s kids — are they good at mathematics too?”
“Not really.” Xie Yichen said. “My cousin genuinely cannot stand mathematics. It’s at the level where even if someone at home mentions it casually, he immediately finds a way out of the conversation.”
“That bad?”
“Yeah. He has no interest in science and engineering — he much prefers gaming.” He said, measured and unhurried. “During the last winter holiday, he went behind my aunt’s back and started a competitive gaming livestream. Apparently made quite a lot of money.”
Ning Sui looked at him, blinking slowly: “I’ve noticed your family members are each extraordinary in their own way — no matter what path, money finds its way to you.”
She cleaned her palm and catalogued them, counting on her fingers with complete seriousness: “Look — your cousin plays games, your older cousin makes short videos, and then there’s you — you take on clien—”
“?”
She caught his expression and realized she’d said something wrong. She swallowed: “Ah — no, I mean, you take on commissions.”
“……”
She’d heard from Liu Chang that in the ruthlessly competitive environment of the Yao Class, he was simultaneously writing code for small private enterprises. It was simply not human.
Ning Sui buried her face, and sincerely asked: “Are you one of those so-called time management masters? Otherwise, with the same twenty-four hours as everyone else, how do you study and still have time to do all these other things?”
Time management master, her foot.
Xie Yichen pulled at the corner of his mouth and stared straight at her: “And what about you — thriving across sports, arts, and academics, with thirty-two credits worth of courses, and still managing to join that many clubs and activities.”
He paused, then narrowed his eyes slightly with an expression that was hard to read, and drawled: “Including, apparently, not forgetting to attend the student festival at another university’s school.”
Ning Sui: “……”
Wait, how did he know about that too.
Did that mean he also knew about the public confession she’d received there?
Oh no……
Ning Sui still remembered how mortifying it had been. The Student Festival was something Hu Ke’er had dragged her to, claiming a senior from her own department was absolutely insisting she come watch their street dance club perform — and then, who could have predicted, during one of the later acts, a computer science student suddenly shouted Ning Sui’s name mid-solo and confessed, so overcome with emotion he nearly cracked on a high note.
There was a large side screen, which he’d apparently arranged in advance with the venue manager, and it started scrolling Ning Sui’s name and department on a loop.
[Ning Sui, gorgeous Mathematics Department goddess! I love you!]
[Ning Sui, gorgeous Mathematics Department goddess! I love you!]
[Ning Sui, gorgeous Mathematics Department goddess! I love you!]
Without exaggeration, in that moment Ning Sui had genuinely wanted to roll her eyes back into her head and faint on the spot, to depart this world and sever all earthly ties.
Afterward, she and Hu Ke’er asked around before finally piecing it together — Hu Ke’er’s senior was that computer science student’s friend, who had gone specifically to help him set it up.
As for how Xie Yichen knew — it was definitely Hu Ke’er who’d told him.
She really needed to have a serious talk with that girl when she got back. Stop running around spreading everything to everyone.
Ning Sui silently raised her beer can and took a very pointed sip, pulling a layer of composure over herself: “I was just enriching myself. It’s not easy to get into university — you have to live it to the fullest.”
The weather was lovely tonight. Even deep into the evening, the clouds and sky were still clearly defined — you could make out the dark layer of cloud slowly rolling over the moon, and when the wind carried it through, the pale white moonlight would emerge again.
A little farther off, there were faint pinpoints of starlight, softly glimmering.
The film had ended at some point. The club members at the front were dismantling the large screen setup, and the students scattered across the field were getting up contentedly one by one, gathering their things and departing in groups of twos and threes.
Ning Sui tilted her head back to look at the sky, and gazed for a long, long moment. She felt the sky tonight was particularly beautiful and clear — like the mirror of someone’s innermost heart.
“Actually, I still haven’t figured out what I want to do with my life.” Ning Sui said. “I only know that for now I should keep accumulating knowledge and studying hard, so that in the future I’ll have more choices available to me.”
She turned her head. Her dark eyes were quietly bright as water: “What about you? You’ve probably already thought about this, haven’t you?”
Xie Yichen glanced sideways at her, paused a moment, then also looked up at the sky.
After a long while, he spoke in an unhurried tone: “I have thought about it, but I haven’t settled on an answer yet either.”
He folded one knee up and rested his arm on it casually. “My older cousin is one of the lucky ones — he knew clearly from a young age what he wanted to do with his life. But honestly, most people, at our age, are pretty lost.”
“That’s exactly because I haven’t figured it out that I want to explore and try more things.” Xie Yichen gave a slight laugh, glancing at her with careful attention. “Actually, I don’t want to decide too quickly. Sometimes the process matters more than the outcome.”
He didn’t like a life that was unchanging and without surprises. Ning Sui thought — she didn’t either.
The more time she spent with Xie Yichen, it seemed, the more she could appreciate the beauty of living as an experientialist.
Doing what you want, unbound and free to be yourself.
Many sights had to be seen with the eyes. Many feelings had to be touched by the heart.
The mat spread over the grass was fairly large. Ning Sui simply lay back on the lawn, relaxed, looking up at the sky, letting the mellow warmth of the alcohol spread through her.
She said: “Even though I haven’t figured out what kind of person I want to become, there are so many things I want to do. I even have a list — every time I finish something, I check it off.”
Xie Yichen was mildly curious: “Like what?”
“Like taking a spontaneous trip — did that during the summer holiday in Yunnan.”
Ning Sui smiled, recalling the contents of her list. “And lots of other things. Flying to a city I don’t know and watching a concert, attending a book signing for an author I love, or getting my hair permed into big waves, dyeing it pink… oh, and also: scaling a wall.”
“Scaling a wall?”
“You know, in TV dramas when kids sneak out to eat late-night food or go to an internet café — they always go over the wall, don’t they?” Ning Sui said earnestly. “I was a three-good student every year in school, so I never did any of that. I kind of always envied them.”
Xie Yichen also lay back beside her, a laugh shaking his shoulders.
Ning Sui thought — could he please not make even his laugh sound so appealing. Low and lazy, with a trace of warmth woven through the breath of it.
Drinking did make you bolder, didn’t it.
She let out a slow, tipsy little hiccup: “I’ve named this bucket list of mine the ‘Go Completely Off the Rails List.'”
Xie Yichen looked at her from the side. A strand of Ning Sui’s hair near her temple had gotten tousled and was sticking up — she looked a little silly.
Impossibly endearing.
He suppressed the urge to reach over and smooth it down: “Well then — what if we find a wall right now to climb over, and make that wish come true for you.”
Ning Sui hadn’t been drunk before — she had no idea what state she was in at this point.
She nodded, a strange excitement welling up: “Really?”
Xie Yichen’s voice was low and muffled, a quiet laugh in it: “Shall we go now then?”
“Let’s go!”
He had already propped himself up lazily on one arm, beginning to sit. Ning Sui glanced sideways up at him, her heart wavering for a beat, then she meekly asked: “If we get caught, what’ll happen to us?”
Xie Yichen teased her: “Not sure — minor penalty at best, expulsion at worst, probably.”
“Ah?” Ning Sui’s eyes went wide instantly. She genuinely considered this for a moment, then asked: “Can I negotiate something with you?”
“Go ahead.”
She pressed her lips together with an expression of great difficulty, weighing things out for a moment: “If we do get discovered — could you sacrifice yourself and be the last one out, and just… throw me back over the wall to the inside?”
“……”
Fortunately Tsinghua’s campus was spacious enough. Xie Yichen found a spot that reasonably satisfied the requirements of this particular drunkard.
It was a secluded corner not far from the northeast gate. The wall was neither too high nor too low — roughly the height of a full-grown adult — with no electric fence at the top. Xie Yichen recalled that there were many plants on the outside, and landing on the other side should be on soft grass. It was also quite hidden.
Ning Sui tilted her head back to look, then very self-awarely stepped back: “You go first.”
“……”
Xie Yichen was tall with long legs. He found the uneven footholds on the wall and scaled it with ease, sitting astride the top with effortless composure.
Ning Sui felt certain he had done this kind of thing quite a lot back in school — he looked exceptionally practiced, entirely in his element, effortlessly cool. When it came to her own turn, she had no idea how to go about it — she couldn’t even reach the top of the wall, and could only try propping herself up by stepping on the brickwork below.
The round little pompom on top of her beret bounced and bobbed as she moved, making his heart itch.
“Give me your hand.” Xie Yichen’s voice was low.
“…Oh.”
Ning Sui was actually quite nervous — she had never done anything like this before, and she hadn’t imagined that someone, upon learning of her wish, wouldn’t laugh at her for being childish but would instead say without a second thought that they’d go with her to make it happen.
The thick layers of clothing somewhat hindered her movement. Ning Sui stretched her arm out as far as it would go and placed her fingertips into his right palm.
She’d assumed this would be a complicated process, but Xie Yichen’s left hand gripped her other wrist firmly, and a flex of his forearm pulled her right up.
Ning Sui steadied herself with one hand on the top of the wall, a light and fleeting support of his palm at her waist, and she found her balance.
Separated by the puffiness of the down jacket, the sensation was dulled, but she quickly adjusted her position, and the two of them sat shoulder to shoulder at the top of the wall.
— Even having made it up, she still felt a sense of unreality.
Her whole body was light, and the alcohol had softened everything further.
Looking at the moon from this spot, the moonlight seemed somehow gentler and more luminous.
All around was quiet — so quiet it felt as if you could hear two people breathing faintly in the dark.
Below grew a cluster of osmanthus, tiny pale-yellow blossoms. Yet they breathed out an extraordinarily rich and heady fragrance that the light breeze carried straight to their faces.
Ning Sui’s heart was beating a little too fast. The fingertips that Xie Yichen had held just now were still warm, with a soft, faintly tingling sensation.
Not far off, the lights at the northeast gate were still on. Ning Sui had the persistent feeling that the security guard would come around on patrol any moment. She stealthily lifted her lashes and snuck a look at the person beside her.
He was also looking up at the moon.
The distinct, evenly-spaced lashes hung lazily low. The bridge of his nose was high, and while his profile was sharp and refined, somehow, no matter how you looked at it, there was a kind of quiet, gentle warmth tucked just beneath the surface.
Ning Sui was lost in looking for a moment. Just as she was about to pull her gaze back, Xie Yichen seemed to sense it and turned to look at her.
Those dark, fathomless eyes were slightly deep in expression, but threaded through with tiny flickering light.
It was the reflection of the street lamp nearby.
He seemed to want to say something. Ning Sui’s lashes flickered, and she looked away without drawing attention to it: “We should get down quickly.”
The surrounding sounds seemed to have been softened and warmed by the moonlight. Ning Sui heard Xie Yichen give a low hum of agreement close to her ear.
After a moment, he swung himself around, carefully looked down to assess where he’d land, confirmed the landing was safe, and simply dropped down.
He had stayed long enough up there. Old Qu had mentioned once that the security at the northeast gate was fairly relaxed — the guards didn’t patrol this side much. There’d been a time in the middle of the night when Qu Handong wanted to go out for a midnight snack, and this was the route he’d used.
Liu Chang had asked why not just use the main gate.
Qu Handong had answered with delight — because it’s thrilling.
It was only now, standing on the ground waiting to catch Ning Sui, that Xie Yichen was reminded of a rumor whose origin he’d long forgotten — that this spot had supposedly been a well-known location for couples looking for privacy. Allegedly, students coming back from late-night study sessions had, on more than one occasion, heard very strange sounds coming from this area.
He still remembered the way Qu Handong had described it, very vividly and expressively: “Apart from voices, there were the sounds of leaves — because there were a lot of shrubs in that area.”
Now, Ning Sui was perched hesitantly on the wall, both hands pressing down on her pleated velvet skirt, looking down at him with lowered lashes.
The night was too thick. Her ears were probably a little pink, though Xie Yichen couldn’t quite make it out in the dark. His mind was currently occupied by that rumor. He opened his arms, voice dropping into a low, rough warmth: “It’s alright. I’m here to catch you.”
It was past midnight — close to one. The road still had cars driving by in both directions, but the trees nearby, of some unknown variety, had grown quite tall and formed a canopy around the area, making it difficult to see clearly from outside.
But Ning Sui was sure she could hear footsteps approaching, and feared it might be the gatekeeper.
Her heart seized. Her legs went suddenly soft, and she dropped straight down.
Everything happened in an instant. Ning Sui fell directly into Xie Yichen’s arms, instinctively grabbing for anything to hold on to, her hands latching around his neck like someone clutching a lifeline.
Xie Yichen had also been drinking, and his guard was down — her momentum hit him squarely and sent them both backward, his back pressing deep into the soft grass.
A dull, muffled thud against the ground.
The golden fallen leaves scattered all around them crunched and crackled under the impact.
Ning Sui’s face pressed directly into the crook of his neck. Her lips seemed to brush against warm, dry skin.
A current-like sensation swept suddenly through all her limbs. Above her head, his breath passed over her, deep and scorching. In that instant, all she could hear was the heavy, dull pounding of her own heartbeat, beating hard and low.
The young man’s broad, sturdy chest rose and fell beneath her with controlled steadiness, and Ning Sui felt the heat rising to her cheeks, her entire body warm and dizzy.
Ning Sui braced a hand on the ground beside him and tried to push herself up, but couldn’t get the angle right and had no strength in her arms. Her hair had all fallen loose, draping entirely across his neck.
She was still shifting and struggling when Xie Yichen suddenly grabbed her wrists.
He closed his eyes, lips parting just slightly. His voice was extremely low and rough: “Don’t move—”
Ning Sui had been rattled by the fall and was so tense she was biting her lip, her lashes shaking without stopping. The two of them both went rigid, and after something like ten seconds she managed to roll herself off and to the side.
At that very moment, a beam of torchlight came sweeping over without warning, and a voice — exasperated but kept deliberately quiet — said from outside the wall: “You young people, hm? There really is no concept of timing. Look how early it still is — cars still going by out here in a stream. I can’t just turn a blind eye to this every time!”