He was a disabled military officer who doted on his research work in the Northwest.

The third evening was dedicated to tutoring in geography.

When discussing the Coriolis effect caused by Earth's rotation, he casually remarked, "The upper-level airflow in the Northern Hemisphere deflects to the right. You can clearly feel the crosswind when flying over the China-Mongolia border..."

Then it abruptly stopped, and the textbook page was turned: "Next knowledge point: Ocean currents."

Shen Tang leaned on the table, resting her chin on her hand, watching him with great interest.

Today she finally realized that he was just showing off.

As they were talking, they "accidentally" drifted into talking about their flying experiences, then suddenly stopped, pretending they hadn't said anything, but the act wasn't very successful.

Because whenever he "accidentally" mentions flying, his voice rises slightly by half a tone, and he speaks a little faster. His usually indifferent eyes gain a brightness—like sunlight reflecting off his pupils from 10,000 meters above sea level.

Then he would casually retract his statement, his face returning to its usual indifferent expression, as if that brief display of boasting had never happened.

In his previous life, Shen Tang had earned a doctorate and had met all sorts of renowned professors and experts. But listening to a top-notch pilot lecture on mathematics, physics, and chemistry while he couldn't help but slip in his own flying-related knowledge was truly unprecedented for him.

She found it extremely fun.

But she didn't expose him, and instead cooperated by showing an expression of great admiration every time he took it back.

Seeing that expression, Mu Qinghan's ears would turn slightly red. Then she would explain the next point of knowledge with even more enthusiasm.

However, Mu Qinghan was not in a good mood about another matter.

After less than a week of tutoring, he realized something was wrong.

Shen Tang's questions are often very accurate—they hit the threshold of knowledge conversion right on the mark.

When she listened to his explanations, he never needed to repeat them a second time; for some complex derivations, he would write down the first two steps, and her eyes would already be following the final result.

It's not that he doesn't know how; it's more like he's deliberately controlling himself so he doesn't learn too quickly.

Like Shen Tang, Mu Qinghan also saw through it but didn't say anything. Leaning back in his wheelchair, he watched the girl opposite him biting her pen and pretending to think, a deep look of inquiry appearing in his eyes.

How many secrets does she hold?

It's okay, he has plenty of patience, he can take his time to see.

They have plenty of time.

……

In mid-October in Northwest China, the autumn wind already carries a biting chill.

Every household in the courtyard lit their coal stoves early in the morning. Stove was also installed in the east wing and the main room, and the smokeless coal inside burned bright red, making the rooms warm and cozy.

The temperature difference between indoors and outdoors is extreme.

That evening, Shen Tang washed her hair. Afraid of catching a cold due to the strong northwest wind, she dried her hair by the stove in the side room, wearing only a thin, light apricot-colored cotton undershirt.

It was too hot inside, so she casually unbuttoned the top two buttons, slightly opening her neckline to reveal a section of her fair and delicate neck and exquisite collarbone.

Since only Mu Qinghan was there, and he was a patient with no feeling in his lower body, Shen Tang subconsciously had no defenses against him.

Holding a physics test paper, she pushed open the door of the side room and ran a few steps to the main room.

"This final problem about acceleration, this step of the derivation feels a bit convoluted to me." Shen Tang pulled out a chair, sat down next to Mu Qinghan, and leaned closer.

Her long, freshly washed hair wasn't completely dry, carrying a faint, pleasant scent of soap, which wafted towards him as she approached. A strand of her half-dry hair fell down, brushing against the back of his hand resting on the table, its cool touch sending shivers down his spine.

Mu Qinghan was grading her homework from the previous day with a red pen. She suddenly leaned in, too close. He subconsciously tilted his head—and his gaze involuntarily fell on her slightly open neckline.

The firelight shone on that skin, giving it a warm glow.

Mu Qinghan's breath hitched for a moment. Her fingers, gripping the red pen, tightened abruptly.

He forced himself to look back at the exam paper.

"Which step?" His voice was a little tense, but he remained relatively steady.

Shen Tang pointed to the third step of the derivation on the test paper, her fingertip less than two inches from his hand: "Here. After decomposing the acceleration direction, I think the resultant force step—"

As she spoke, she looked up at him with a smile.

They were too close. Her breath almost touched his chin.

Mu Qinghan felt his ears burning. He put down the red pen, his tone as calm as possible: "Sit back down and hold the paper further away. It's bad for your eyes to be so close."

"Oh." Shen Tang obediently sat back a little. But only a little—the chair was moved less than half a foot, and the fragrance of soap still lingered around him.

Mu Qinghan took a deep breath and began to explain the problem.

His voice returned to its usual indifference and order. But only he knew that the cap of the red pen in his right hand had been unconsciously clenched and deformed.

Halfway through the conversation, Shen Tang leaned closer again.

"After substituting this formula—" Her finger touched the test paper, and she leaned towards him again. That restless strand of long hair slipped down again, this time landing directly on his forearm.

Soft, slightly cool, with the unique refreshing feel of shampooed hair.

Mu Qinghan's temples throbbed twice.

"Cousin, look here."

cousin.

Those two words again! Frustration burned fiercely on his already taut string like a ball of fire.

"Don't call me that."

His voice suddenly lowered, coming out from his chest with a muffled quality that even he hadn't expected.

Shen Tang's fingers paused on the exam paper.

She looked up and met Mu Qinghan's gaze—his eyes held an indescribable tension, as if he were struggling to suppress something. His jawline was taut, and his Adam's apple bobbed slightly.

"...What?" Shen Tang didn't immediately understand what he meant.

Don't call me that. What should I call you? Cousin?

Looking at Mu Qinghan's almost unpleasant expression, her mind raced.

If not cousin, then what should I call him?

And why suddenly...? Is it because he felt that she, a stranger, was being too intimate and overstepping her bounds?

I remember he said last time that when it's just the two of you, you can just get straight to the point without using titles.

A bitter feeling welled up in Shen Tang's heart.

It was probably out of disdain... His cousin was just a handout he gave her to get her registered in the household; in the end, she was still just a stranger living under someone else's roof.

She slowly sat up straight and silently created some distance between herself. The smile on her face vanished, replaced by a polite but distant formality.

"I'm sorry." Her voice softened. "Then I'll call you Commander Mu from now on—"

Mu Qinghan's face turned even darker.

Commander Mu.

The three words she uttered sounded as stiff as ice crystals, causing a dull ache in his chest.

It hurt him even more than his "cousin".

"Who told you to call him Commander Mu?" he said, almost through gritted teeth.

Shen Tang was completely stunned, and the bitterness she had felt just moments before vanished without a trace. Had she been overthinking things?

My cousin won't do. Neither will Commander Mu.

So what should we call him?

She didn't know how girls of his generation addressed him. She suddenly remembered Su Mingyue from the last time she came; she seemed to have called him Brother Qinghan.

"Well..." She looked at the fine sweat beading on his forehead and his taut jaw, and suddenly realized—he didn't seem angry, he seemed uncomfortable.

Is it leg pain? Or is it a stomach flare-up? He has indeed been experiencing occasional nighttime cramps lately.

Shen Tang softened her voice, leaning closer with a hint of worry, wanting to feel the temperature on his forehead: "Then I... should I call you Brother Qinghan? Are you feeling unwell? You look terrible..."

Qing-Han-Ge.

Three words.

With the deliberately softened tone of her voice meant to soothe, it fell like a red-hot iron ball into the already precarious gap in Mu Qinghan's rationality.

At the same time, her approaching movement stirred up a breeze—the fresh scent of soap, the faint warmth beneath her thin cotton shirt, and those bright, concerned eyes—all sensory information flooded in at the same moment.

Mu Qinghan felt something deep inside her body suddenly jump.

It's not the heart.

It is a more primitive, more instinctive, and more uncontrollable part than the heart.

A strange yet familiar heat surged up from my lower abdomen—a powerful, unstoppable, and overwhelming instinctive reaction.

He froze.

He was frozen in his wheelchair as if struck by lightning.

This reaction was the first time it had occurred since the incident—since he was diagnosed with "fundamental damage and difficulty in having children."

It was so intense that it caught him completely off guard.

But Shen Tang kept getting closer. Her hand had already reached near his forehead, her fingertips cool to the touch, almost touching his skin—