* * *

Jeongseo opened his mouth wide as if to say something, but then turned his head sharply and muttered his response.

“Because we’re friends, of course I like you…!”

Jeongseo pressed his lips tightly together, clutching his chest as though something might burst out if he didn’t.

Sobok, who had been curled up nearby, wagged its tail and licked Jeongseo’s cheek as if signaling it was time to play again.

Jeongseo sprang to his feet.

“I’m going to play with Sobok now!”

He shouted hastily, not waiting for Kanghyun’s reply, and dashed away with Sobok as if escaping.

Kanghyun, watching Jeongseo’s retreating figure, felt a strange, inexplicable sense of disappointment wash over his eyes.

°❀•°❀°•❀°

The final exams marking the end of the first semester of their second year were a month away.

Pyo Yoontae had already started studying with Jeongseo, believing that starting early would yield better results.

The main difference this time compared to the midterms was that Jeongseo and Yoontae had begun to interact more with their classmates.

“Hey, Pyo Yoontae, why does this happen?”

During break time, just after chemistry class, a fellow classmate approached Yoontae.

Since chemistry was held in the fourth-floor science lab, Yoontae, who had been about to leave with Jeongseo, turned around.

Thanks to Yoontae’s outstanding performance during the relay at the sports festival and his change in attitude, their classmates started warming up to him.

On the first day of his transfer, Yoontae had warned, “Don’t talk to me, you pack of brats,” and ignored anyone who tried to approach.

But now, even if he wasn’t warm, he would at least respond.

“What?”

With that brusque answer, the classmate immediately handed over the handout from chemistry class.

Yoontae glanced at it briefly, told Jeongseo to wait, and explained it quickly.

“In a given period, atoms with smaller atomic numbers have larger radii. But in the same group, atoms with larger atomic numbers have larger radii. So the atomic radius increases from oxygen to lithium to sodium.”

“…What’s a ‘group’ and a ‘period’?” Jeongseo’s ears perked up from where he was quietly observing.

He knew this one too. Periods were rows on the periodic table, and groups were columns.

It seemed basic enough, but Yoontae’s face crumpled immediately.

“Are you dumb? Start reading from the beginning.”

Waving his hand dismissively, Yoontae turned as if fed up, while the classmate called out in protest.

“Come on, just one more time!”

“Let’s go, Jeongseo…”

If he entertained any more questions at this level, they’d come back to bother him repeatedly.

Yoontae decided one explanation was enough and moved to leave, but Jeongseo pointed at the periodic table in the handout.

“The rows are periods, and the columns are groups.”

“Ah, whoa. Is that it? So this is one period.”

The classmate drew a line across the table with a pen, which startled Jeongseo.

The student had drawn a line starting from hydrogen to beryllium, then up to scandium, hitting zinc, and finally up to boron and helium—a chaotic mess.

“This is one period, right? Cool.”

Seeing the student admiring their handiwork, Jeongseo asked, bewildered, “Why does the line go down?”

“Huh? There’s nothing above, so you have to fill the gap, right?”

The classmate looked utterly confident in their logic.

Jeongseo, momentarily at a loss for words, let out a faint “Ah.”

He blinked, unsure how to respond.

“Forget it, let’s just go.”

Yoontae grabbed Jeongseo’s wrist and walked out of the science lab.

Their classmate called after them, asking what was wrong, but Yoontae only quickened his pace.

In that moment, Jeongseo wondered if this was how Yoontae felt when teaching him.

“Trying to teach someone like that means they’ll come back with more questions. If I try to explain once, I get so pissed I almost lose it.”

Walking down the central staircase, Yoontae put an arm around Jeongseo’s shoulder and wagged his finger in the air.

“So, don’t be too nice, Jeongseo.”

“Did you feel like you were going to lose it when you were teaching me?”

Yoontae paused mid-step.

Hearing such innocent swearing from Jeongseo’s small, earnest mouth felt strangely off.

He decided right then to use his words more carefully.

While Yoontae reflected, an awkward silence fell, making Jeongseo feel embarrassed and guilty.

He remembered how he’d been before the midterms—barely paying attention in class, even avoiding it.

Maybe he had been even worse.

‘I… I was a huge burden, wasn’t I?’

Jeongseo’s gaze trembled as he realized this, only to let out a startled yelp when Yoontae suddenly bit his right ear.

“What are you doing?!”

Even though Jeongseo flailed in surprise, Yoontae didn’t let go until he’d nibbled lightly before withdrawing.

Feeling his ear slightly damp, Jeongseo twitched in irritation and glared as Yoontae gave him a playful wink.

“Do I look like the type who grudgingly does things I don’t want to do?”

“No, definitely not.”

Yoontae always spoke his mind confidently, even forcefully.

Remembering this, Jeongseo felt reassured and pushed away the nagging memories of his past actions.

This time, however, Jeongseo’s focus was sharper than ever.

He managed to go a full 20 minutes without any distractions, diligently solving the problems Yoontae gave him.

If he kept this up, he would keep his promise to his older brother.

Feeling buoyant, Jeongseo’s steps turned light, making Yoontae’s arm on his shoulder sway with him.

As they neared their classroom, Yoontae suddenly remembered something.

“Oh, by the way, Jeongseo, I won’t be at school Thursday.”

“Thursday? Why?”

For once, Yoontae hesitated.

“I have something to do. I’ll be back Friday.”

Jeongseo was curious, but he could tell from Yoontae’s tone that he didn’t want to elaborate, so he simply nodded.

Thursday was just a couple of days away.

A school without Pyo Yoontae was, as expected, boring.

Still, it was less so with Jeongseo alone, as the other kids walked with him now and then.

Since the sports competition, the students from other classes who had seen Jeongseo’s dodgeball game interacted with him more comfortably, and he had become quite close with several of them.

Moreover, he shared the peaches he received from his grandmother.

Surrounded by his classmates, they poked at the peaches with their broken chopsticks, marveling at how sweet they were, which made Jeongseo feel inexplicably proud.

He also shared the location of grandmother’s peach stand, hoping that her business would do well this year.

It felt strange.

Objectively speaking, he should have been fine without Pyo Yoontae, since he was with his classmates, but that wasn’t the case at all.

All day long, Jeongseo struggled with an inexplicable emptiness.

“Take care, Jeongseo. See you tomorrow!”

“Yeah, bye!”

With Pyo Yoontae absent today, he planned to walk with Sobok as soon as he got home and treat himself to some ice cream.

Jeongseo had devised the perfect plan.

A day without studying wouldn’t be a big deal, after all.

As he happily raced down the stairs, his brown backpack swung with him, the empty side dishes clinking together inside.

Just as he approached the shoe rack, his phone in his pocket buzzed.

[Pyo Yoontae: You finished school, right?] 4:52 PM

As Jeongseo replied that he was done, a KakaoTalk message immediately followed, asking if he was heading straight home.

He bent down to change his shoes when someone stood next to him.

Turning his head awkwardly, he felt a rush of excitement.

“Why are you alone today?”

Hayan was standing there, looking down at Jeongseo with a curious expression.

* * *