class had just started. The chatter of students gradually quieted down as the teacher entered the room. "Open your textbooks to page 30," she announced, her voice commanding. "Today, we're learning about trigonometry."

David, as usual, was already half-asleep in his seat. Wonwoo sat beside him, the top student in the class, always focused and diligent. David, knowing his friend's habit, poked Wonwoo with the tip of his pen. "Hey," he whispered groggily, "you're awake, right? Wake me up when class ends."

Wonwoo, eyes glued to the textbook, simply nodded without looking up. He didn't mind David's constant drifting in and out of sleep. They had been friends for years, and though their study habits were different, they understood each other perfectly.

The lesson went on, and Wonwoo remained absorbed in his work. His focus never wavered, but David's occasional snoring was a reminder that he had more of a laid-back approach to school.

Finally, the bell rang, signaling the end of class. Students began to shuffle out of their seats, chatting and laughing. David stretched, preparing for lunch, but as he glanced to his side, he realized something was off. Wonwoo was gone.

"Maybe he went to the restroom," David thought to himself. He waited for a while, but Wonwoo didn't return. Growing uneasy, he decided to check the hallway. The restroom was empty.

David's heart began to race. His mind raced with worries, but he didn't want to jump to conclusions just yet. He asked a few students if they had seen Wonwoo. One shrugged and pointed toward the exit. "I saw him out on the ground with Jain."

Jain? The name struck David like a cold wave. Jain was the new student who transferred mid-semester from a prestigious school. He was quiet, stoic, and had this unnerving appearance—his pale skin, straight face, and striking yellow eyes. Most students didn't know how to approach him, and Jain had yet to form any real friendships.

David, still puzzled, tried to make sense of the situation. Why would Wonwoo be with Jain? They weren't friends. In fact, David didn't remember ever seeing them interact before. Something felt off.

Worried now, David rushed out the door, heading toward the school grounds. His eyes scanned the area, and his heart skipped a beat when he saw them—Wonwoo and Jain, standing near the trees. But it wasn't just that they were together. What shocked David more was how Jain was holding Wonwoo's hand.

For a moment, David stood frozen, his mind struggling to process what he was seeing. Jain, the loner who barely spoke to anyone, was holding Wonwoo's hand in the middle of the schoolyard. Was this a joke? Had something happened between them?

David's confusion quickly turned into concern. He moved closer, his steps hesitant. Was Wonwoo in trouble? Why hadn't he come back to class?

"Wonwoo!" David called out, trying to mask the edge of panic in his voice.

Wonwoo turned, his face blank, but he quickly pulled his hand away from Jain's grip. "David?" His voice was calm, almost too calm. "What are you doing here?"

David's brow furrowed. "I... I was looking for you. Why are you with Jain? What's going on?"

Wonwoo hesitated for a moment, his eyes flickering toward Jain. Jain stood silently, his usual unreadable expression in place.

"It's... it's not what you think," Wonwoo said softly, his gaze shifting between David and Jain. "We were just talking. He needed help with something, and I—"

David's mind raced as he processed his friend's words. Something didn't sit right. Why didn't Wonwoo tell him about this earlier? Why had he left class without saying anything? And why had he gone to Jain, of all people?

David couldn't help but feel a pang of jealousy, though he wasn't sure why. He had always been there for Wonwoo, but this felt different. There was an unspoken distance between them now, one that hadn't been there before.

"I'm... I'm sorry," Wonwoo added, his voice quieter now. "I didn't mean to worry you."

David shook his head, trying to make sense of everything. "You shouldn't just disappear like that, especially with someone like him."

Jain's eyes narrowed ever so slightly, but he said nothing. He didn't need to. His silence said more than enough.

"Let's just go back to class," David muttered, his worry turning into frustration. "We'll talk later."

Wonwoo nodded, but as they began walking back toward the school, David couldn't shake the uneasy feeling in his stomach. He didn't know why, but this moment felt like the beginning of something much bigger. Something he wasn't sure he was ready for.

This revision improves the pacing, adds more emotional depth, and better develops the characters and their relationships. It builds more suspense around Jain's mysterious nature, David's concern for Wonwoo, and the overall situation. Hopefully, this captures the tone and tension you were aiming for!