The film base in the northwest was where they would shoot the scenes of Shen Yao after returning to China.

In this part of the film, Gu Yi took centre stage. He had to make Shen Yao’s scientific process appear both professional and compelling—even though the actual work might be tedious, Shen Yao’s rigor and resolve, and the story of a group of scientists striving toward a dream, had the power to move people.

Gu Yi was ushered into the makeup room and had his hair cut short.

The stylist gave him a pair of glasses and helped him into a lab coat. As he stood for his character photo, the female lead Qi Miao let out a quiet gasp.

She was a fan of A Letter on My Desk long before it became a film. When the adaptation was announced, she had actively sought out the role of Yu Ying, the female lead. For the male lead Shen Yao, Qi Miao had already mentally shortlisted several actors from the industry whom she thought suitable.

She hadn’t expected Sun Youming to choose Gu Yi.

On photos alone, Gu Yi certainly looked like Shen Yao. But Qi Miao was still anxious.

As both a co-star and a long-time fan of the book, she really didn’t want the character of Shen Yao to be ruined.

Qi Miao primarily acted in films and had little experience working with idol-turned-actors. But she’d heard enough industry gossip—how some idols couldn’t act, slacked off on set, needed hours to memorize a single page of lines, and did little more than pose for the camera.

Even with Sun Youming directing, she couldn’t fully relax.

But in that moment, all she could think was:

“He’s so handsome.”

Gu Yi’s aura was perfect for Shen Yao. She hadn’t felt it when they first met, but the moment he changed into costume, it was as if the character had stepped right out of the novel.

Shen Yao was always described with a cool, aloof demeanour. And when Gu Yi looked expressionless, that sharp, reserved edge came through vividly.

No wonder Sun Youming had ignored all the big-name actors and chosen an idol like Gu Yi.

On the fan forums Qi Miao often visited, many had hoped Xin Ruchen would be cast instead. If she hadn’t seen Gu Yi in character, she might have agreed with them.

But now… after seeing his transformation, she quietly changed sides.

---

The first scene to be filmed was Shen Yao’s laboratory sequence. In the script, Yu Ying hadn’t returned to the country yet. Shen Yao, upon arriving home, was met with a broken, battered lab and a country still lacking basic research equipment.

He was angry.

His former rival had once mocked him, saying his homeland would never use advanced pharmaceuticals. That even if Shen Yao returned, he’d never be able to change anyone’s fate.

But the bleak reality didn’t break Shen Yao. It only made him more determined.

Director Sun Youming walked Gu Yi through the scene—starting with blocking, then explaining how to find the camera, and how to express the character’s emotions. Gu Yi opened his notebook and carefully wrote everything down, word for word.

Gu Yi had created a personal character profile. Sun Youming handed him another one—his interpretation vs. the one the film needed him to portray.

“Xiao Gu hasn’t acted before, has he?” said Wu Qingchun, who played another chemist in the film, chuckling. “Director Sun’s got his work cut out for him.”

Qi Miao stayed quiet.

Wu Qingchun wasn’t famous and had never played a leading role, but he had deep roots in theatre, and his peers were scattered across the industry.

From the way he said it, Qi Miao could tell what he was implying—and she remembered Wu Qingchun was in the same agency as Xin Ruchen.

---

In the first scene, Shen Yao and his colleagues cleaned the dilapidated lab. There was barely any research material left, so Shen Yao had to rely on his memory—writing out experiment plans, page by page, from scratch.

“Action!” Director Sun raised the megaphone. “Everyone, places!”

The set was ready, actors in position. But as soon as the camera rolled, Sun waved his hand and shouted,

“Gu Yi! You’re in the wrong spot. Where are you even looking?”

Someone on set chuckled.

“Reset!”

Sun Youming was known to be easy-going, and he welcomed advice when he was the one making mistakes. But on set, during filming? He was strict—ruthlessly so.

“Gu Yi, you’re blocking the others. Back to your mark.”

It was obvious to the cast: Gu Yi had zero acting experience.

Blocking was Acting 101. If he couldn’t even manage that, it was natural for the others to worry.

“Why’d he cast someone with just a face?” Wu Qingchun muttered to the camera crew. “How long are we gonna have to wait on this guy?”

Wu knew Sun’s temper. If Gu Yi kept making the same mistakes, Sun would absolutely explode.

But the explosion never came.

Instead, Sun pulled Gu Yi aside and calmly walked him through everything again.

“Don’t be nervous. Just take it step by step.”

To Wu Qingchun, that confirmed his suspicions: Gu Yi had only gotten the role because he was under contract.

He glanced over at Gu Yi and thought, Kids these days sure have thick skin.

Sun Youming had already scolded him in front of everyone, and yet Gu Yi’s expression didn’t change at all. If it had been Wu in his youth, he’d have been too ashamed to show his face on set again.

---

This time, Sun’s patient coaching seemed to pay off.

Gu Yi finally stood in the right place. He even learned how to find his angle for the camera.

But if it took him this long just to nail the basics, how was he going to handle the rest of the film?

The cast waited, on edge, expecting Sun Youming to start yelling any second now.

But…

The shouting never came.
And not only that…

The crew couldn’t help but blink in confusion.

Just moments ago, Gu Yi couldn’t even hit his mark properly. Yet now, in the lab-cleaning scene, it was as if he were possessed by some higher force. He knew exactly how to handle each piece of equipment—how to clean, where to place it. While the rest of the actors had prepped by rote memorization—beakers, test tubes, crucible tongs, tripod stands—Gu Yi delivered his lines and instructions like he was reciting a fluent chant, guiding the others through their tasks with effortless familiarity.

And his aura—completely transformed from when he was being scolded earlier.

To the cast, it didn’t feel like Gu Yi was acting as a seasoned chemist. It felt like he was one. He seemed to know the lab inside and out, assigning tasks like a true team leader. His presence commanded the scene, and the performance came together naturally under his rhythm.

Everything looked incredibly authentic. Especially the parts Gu Yi handled himself—if you weren’t a chemistry expert, you wouldn’t be able to spot a single flaw.

What was going on?

Everyone was puzzled—especially when the moment Director Sun Youming called “Cut!” and moved to the next scene, Gu Yi once again fumbled his mark.

So… did he have experience, or didn’t he?

On one hand, he clearly needed direction—Sun and the assistant director had to guide him through basic filming logistics. Gu Yi didn’t hesitate to ask questions or learn from more experienced actors.

But on the other hand…

The cast watched, dumbfounded, as Gu Yi used a crucible to heat a compound until a white powder formed, with the precision of someone who had done it a hundred times before.

When he was truly focused, Gu Yi didn’t look like he was acting. He looked like Shen Yao—body and soul.

In all their years working on sets, the actors had never met someone quite like him.

Say he’s good, and he suddenly flops. Say he’s not, and he turns around and nails it.

“Cut! The emotion’s not right,” Sun Youming said. “You need to think carefully. In that era, what was Shen Yao feeling first?”

Gu Yi struggled repeatedly with conveying Shen Yao’s anger. Each time he thought he had the emotion ready, Sun would tell him it was still too thin—too shallow. He needed to go deeper.

“Don’t rush,” said the assistant director, patting Gu Yi on the shoulder. “You can’t just look at it from our time. Think about what Shen Yao would have felt in his own time.”

The assistant director could tell—Sun Youming was actually quite satisfied with Gu Yi.

The role of Shen Yao had been notoriously difficult to cast. The crew had held two full rounds of auditions. Several actors the assistant director thought were solid picks had all been rejected by Sun.

Until today’s shoot, the assistant director hadn’t understood why.

But now, he got it.

Four words:
It just felt right.

Even a more technically skilled actor wouldn’t have been able to be Shen Yao the way Gu Yi was.

---

Gu Yi mulled over Sun and the assistant director’s comments.

As someone with a background in chemistry, Gu Yi had often heard people say that the field was lagging behind internationally. He felt frustrated by it, of course—but with time, he had come to accept the reality of the gap. After all, no amount of anger would instantly close it.

But Shen Yao…

He had lived in a time when the country was at its weakest. The disparity between nations had been even starker. And Shen Yao had known that all too well.

So—what exactly was he angry about?

Gu Yi closed his eyes and tried to inhabit the role completely.

A Letter on My Desk chronicled Shen Yao’s entire life—his youth, his education abroad, his return to China, and ultimately, his self-sacrifice near the end.

Gu Yi had memorized every line of the screenplay by heart.

He’d read the original novel ten times, each time in earnest.

He sat there a long while, combing through every word, every sentence he’d read and rehearsed.

In the end, Shen Yao had walked toward death with a smile.

“Gu Yi, are you ready?” Sun Youming asked, approaching.

“Give me thirty more minutes,” Gu Yi replied.

“Alright,” Sun nodded. “Take your time. No need to rush.”

Sun meant what he said. He hadn’t expected this scene to go smoothly—it was a complex, technically demanding moment that couldn’t be faked. But Gu Yi’s rhythm had lifted the entire cast, and what was supposed to take hours had already been cut in half.

To Sun, Gu Yi wasn’t exactly without talent. He just needed refining. And with time, that rough edge could polish into brilliance.

“How much longer is this going to take?”

Once again, it was Wu Qingchun complaining. He’d already pestered the assistant director earlier, who, used to Sun’s temperament, had brushed him off with:

“Go ask Director Sun yourself.”

But Wu wouldn’t dare. His credentials meant nothing next to Sun Youming’s.

He still remembered how one of his seniors had tried to act high and mighty around Sun—and had been kicked off set on the spot. No amount of posturing or industry clout had saved him.

Now, as Wu looked up, he saw Gu Yi rise from his seat.

“Director, I’m ready,” Gu Yi said.

Under the scorching sun, Wu couldn’t make out Gu Yi’s expression clearly.

But he could feel it—

There was something different about his stance.
Something steadier.
Something stronger.