— You’re scared of the dark, aren’t you.

The opening notes of the film’s score swelled at that exact moment, swallowing all other sound.

In the nearly empty cinema, Xie Yichen held the light. All Ning Sui could see were those dark, striking eyes.

The light seemed to become a candle flame, swaying slowly in the space where their gazes met. She blinked without meaning to.

She looked at him and said nothing. For a very short moment there was a stillness in her chest — one second, perhaps two — and then the screen started playing advertisements, flooding the entire hall with light.

The torch was no longer needed. Ning Sui watched beside him as he unhurriedly put his phone away, and the two of them walked up together. When they reached the right row, Xie Yichen stepped aside again, gesturing for her to go in first.

Ning Sui noticed he was consistently attentive in these small ways — the kind of boy with a genuine sense of consideration.

They settled into their respective seats. It wasn’t long before the lights dimmed fully, the rich, resonant score began, and the film started without preamble.

It had to be said — Russell, the actor playing Nash, gave a truly remarkable performance, conveying through expression and movement alone a genius, a man so utterly consumed by the pursuit of truth that he lost himself entirely in it.

Mathematics was a great and mysterious thing — capable of weaving dull and abstract knowledge into something altogether new. Ning Sui had felt that spark herself, that flash of sudden clarity when everything connects. It was bewitching. That fleeting beauty made you want to hold onto it forever.

She wouldn’t have suggested this film to just anyone — but she felt that Xie Yichen, specifically, would understand it.

At a certain point the film gave Ning Sui goosebumps from Russell’s performance alone. The cinema was completely silent. Her throat was dry — she took a sip of Sprite, and reached instinctively into the bucket for a piece of popcorn.

Xie Yichen happened to reach in at the same moment. Their fingers collided, completely without warning.

Ning Sui’s fingertips were ice-cold from holding the cold drink. Xie Yichen’s palm was warm. The contrast was sharp enough that she paused without thinking.

Xie Yichen reacted first, pulling his hand back quickly, his voice low: “Sorry.”

The sensation still lingered at her fingertips. Ning Sui rubbed her palm lightly against her leg beneath the armrest.

She’d never noticed before, but the seats were actually quite close together. She pressed her lips together: “It’s fine.”

Two hours passed quickly, especially when two people are both genuinely absorbed.

The film was quite heavy in tone, particularly toward the end — Ning Sui watched it with a furrowed brow. She thought of something Aristotle had once said: “No great genius has ever existed without a touch of madness.” It seemed strikingly apt.

Ning Sui concluded she was probably not a genius, because compared to the sleepless, foodless Nash, she was clearly far too cheerful and unconcerned. Even during the most grueling stretch of Year Two, she’d go hungry after a single skipped meal, and before evening study hall had even started, she’d already be deliberating whether to get Yangzhou fried rice or scallion-and-egg dumplings for her late-night snack.

After the screening ended, a few people in the front rows sat for a long time before finally leaving. Ning Sui glanced sideways at Xie Yichen. His head was slightly bowed, dark hair falling across his forehead, brow faintly drawn, long lashes quietly lowered — as if he was thinking about something.

But that mood lasted only a moment — it came and went without a trace. Xie Yichen raised his gaze, clearly registering that she was watching him, and asked with perfect composure: “What?”

“Do you know what this film is actually trying to say?” Ning Sui said suddenly, as if a thought had just struck her.

“What?” He raised his brow.

Ning Sui said gravely: “That studying mathematics for too long will drive you insane. I should probably be more careful.”

“……”

Xie Yichen clearly hadn’t expected her to emerge from two hours of cinema with that as her profound takeaway. He didn’t hold it in — a quiet laugh broke through his nose.

He folded his arms and rested back against the seat, listening as she continued to hold forth with great conviction, his tone sympathetic: “If Nash had gotten the Fields Medal at the very beginning, he probably wouldn’t have lost his mind at all.”

When all was said and done, the organizing committee had simply waited too long to give out the honor — and drove the man to spend his days obsessively racking his brain. Anyone would become consumed.

Xie Yichen said: “Then game theory wouldn’t exist either.”

His whole chest shook lightly as he laughed. Ning Sui unconsciously touched the tip of her tongue to her lips: “Well. That’s also true.”

The two of them chatted as they made their way out. It was past ten, nearly eleven — the old town’s streets were still alive, filled with people, lights spilling everywhere in every color. Ning Sui asked casually, “Xie Yichen — if you had to choose, would you rather have your mental health, or would you rather have fame and fortune?”

Mid-sentence, she caught him casting a look of disbelief in her direction.

Ning Sui: “?”

Xie Yichen: “Why not have both?”

Ning Sui: “……”

Right then.

The shops on either side were dazzling, full of delicate, charming goods. The person walking beside her strolled along at a leisurely pace, glancing at things as he passed. At last, in a low, unhurried voice: “Actually, the two aren’t contradictory to begin with.”

“Hmm?”

Ning Sui came back to herself a beat later, realizing he was answering her earlier question.

“Life doesn’t have hurdles you can’t get past. Don’t overthink it — the harder you fight it, the more it blocks you, until you’ve backed yourself into a corner.”

Ning Sui held up a crystal bracelet from one of the roadside stalls against her wrist, turning it over in thought: “But it’s easy to get tunnel vision when you’re in the middle of it. When you’re right at that last step before breaking through, it’s genuinely hard. You keep trying and it never works — but you still feel like you could make it work. And with all that sunk cost ahead of you, walking away isn’t easy.”

“Of course.” Xie Yichen smiled slightly. “Just like Nash — he really did become a great mathematician by doing it that way. It’s just that different people make different choices. If it were me, I wouldn’t be that stubborn about it.”

If one path doesn’t work, you find another. If that doesn’t work either, you find a different goal altogether. There’s always something you’re good at — no point in driving yourself to madness over it.

Beneath the warm, encircling glow of amber lantern light, his voice was unhurried and free: “I’ve always believed that when one road is blocked, another will open. Every road leads to Rome — just like Euler’s theorem, which has more than one proof.”

Something jumped quietly at the tip of Ning Sui’s heart: “That line…… I feel like I’ve heard someone say something like that before.”

Xie Yichen’s gaze drifted down slightly: “Is that so.”

“Yes.” Ning Sui paused briefly. “I was also doing math competitions in Year Two. Maybe it was all the problems I was grinding through — I had a bit of that same mentality of grinding myself into the ground…… Fortunately I got out of it eventually.”

A band was singing rock music with full force from the bar next door. Ning Sui caught Xie Yichen gazing in that direction for a moment, before he asked in his unhurried way: “How did you get out of it?”

“There was this question-and-answer website for math competition students — Leonhard Euler — with lots of brilliant people from Tsinghua and Peking University on it. You’ve definitely heard of it. I started out just posting problems I couldn’t solve, but eventually I changed to just venting on there, and somehow got into a conversation with someone.”

Ning Sui said, “That person became something like a pen pal for me. When I was struggling, I’d talk to them, and gradually I found my way through.”

It was a strange kind of fate, thinking about it. Ning Sui still didn’t know who that person was to this day — but the two of them had gotten along surprisingly well, exchanging messages on and off for nearly an entire school year, covering everything from life philosophy to astronomy and geography, nothing off the table.

She’d even quietly told that person that she was avoidant attachment in relationships.

For a stretch of time, Ning Sui was always buried in her phone, which had led Xia Fanghui to become thoroughly convinced she was secretly in a relationship.

Why does anyone bother learning mathematics?

When Ning Sui had been close to breaking point, she’d asked Ning Deyan through tears and sniffles. Her father had gently patted her on the head and said, “So that in the future, when you’re bargaining at the wet market, no one can cheat you. Oh, and also — to prove that learning English is easier by comparison. Life is hard; treasure every moment.”

What kind of answer even is that. She’d been so irritated by his nonsense she’d almost wanted to hit him.

But she had to admit, her small reserve of optimism was absolutely genetic — inherited from her father. Without it, there was no way she’d have maintained that level of psychological stability through Xia Fanghui’s relentless bombardment of negativity in Year Two.

She’d asked her pen pal the same question: 【Why do people bother learning such difficult mathematics? If all you want is to haggle at the wet market, wouldn’t understanding that one plus one equals two be enough?】

Her pen pal had replied: 【Because you won’t only ever go to the wet market. You might sit on a Ferris wheel by the sea. You might wear a formal dress to a classical music concert. You might want to understand why the sunset is so beautiful, or how far the stars are from the sun.】

【Humanity’s ancestors invented many brilliant ways of engaging with the world. We still don’t know how vast the universe is, but we hope to measure it with our own hands nonetheless.】

Ning Sui didn’t know who that person was, but she felt certain they must be someone who lived with a great warmth for life.

At a time when she’d been ground down and breathless with pressure, those spirited words had genuinely encouraged her.

They had reminded her that even at dusk, you could still look up and find the sunset and the evening glow.

Xie Yichen stepped steadily over the stone-paved road, dragging the sole of his shoe across a thin layer of green moss. He had his dark eyes half-lowered, looking at her in an unfocused, distracted way: “Did you two stay in touch after that?”

Ning Sui’s lashes stirred slightly. She answered quickly: “No.”

“When I was in Year Three, I got a new phone and accidentally lost my password. I couldn’t log back into my old account.”

She paused a moment. “And things were so busy with school. Once math competitions didn’t work out, I just focused on the university entrance exams.”

Xie Yichen bowed his head again to look at the shadows on the ground, his reply languid: “Mm.”

At that point his phone started buzzing in his pocket — a call from Zhang Yuge, which was hung up almost before it connected, as if he’d had a sudden change of heart. Impatient as ever.

Xie Yichen also saw a string of WeChat messages from him popping up.

Earlier, when Xie Yichen had changed and headed out, Zhang Yuge had still been on the phone, earnest and careful. Clearly his mother’s interrogation had ended, he’d discovered he’d been left behind, and was now hopping around in a panic.

Before leaving, Xie Yichen had left him a note saying he was going for a walk around the old town.

Jin Ge: 【You went out alone in the middle of the night? 😊】

Jin Ge: 【What a poetic soul???】

Jin Ge: 【I’m done with my call, get back here RIGHT NOW!!!】

Several dozen minutes later.

Jin Ge: 【I’ve played several rounds of the game already, where are you?? Which ditch did you fall into?!】

Jin Ge: 【Yichen? 😊】

Jin Ge: 【Xie-lord!】

Jin Ge: 【Big bro!!】

Jin Ge: 【Get OUT here!!!😊】

And then just now — he’d sent a bright yellow red packet: a transfer of thirty-eight yuan. Xie Yichen happened to see it and tapped to collect it without thinking.

From Zhang Yuge’s perspective, the timing of that was infuriatingly casual: 【Are you serious right now?!】

Jin Ge: 【I’ve been looking for you forever and the second I send a red packet you materialize — and that nickname I gave you in my contacts is EXACTLY right!!!😊😊😊】

Admittedly, from where he was standing, that was exactly how it looked.

Xie Yichen paused briefly. Beneath the red packet notification, he sent back two words.

Scumbag: 【Thanks.】

Still quite polite.

Zhang Yuge was seething — he sent two voice messages in a row, both over ten seconds long. Here the bar was blasting music, and Xie Yichen couldn’t even be bothered with the voice-to-text function.

Scumbag: 【Sure.】

Scumbag: 【Don’t wait up. Go to sleep.】

Jin Ge: 【What do you mean sure! I’m asking you about tomorrow’s plans — what time are we getting up!】