The sun hung low in the sky, casting a golden hue over the room. Kazuki leaned back in his chair, eyes glued to the pile of books and papers strewn across his desk. Despite being a high school student, it seemed like there was always something to study. But today, the focus wasn't on his own schoolwork. Instead, his attention was devoted to someone else—his little sister, Aoi.
Aoi, who was two years younger than Kazuki, was a high school freshman. She had always been a bit of a handful—especially with her overprotective nature and strong attachment to her older brother. But there was more to Aoi than just her obsession with him. Beneath her slightly possessive exterior, she was a diligent student who always aimed to excel in everything she did.
Today, however, she was struggling with her studies, particularly math. Despite her best efforts, she couldn't quite seem to grasp some of the concepts her teacher had gone over. That's where Kazuki came in.
Aoi sat at her desk, a notebook filled with messy, half-finished equations, her brow furrowed in concentration. Kazuki watched her from across the room, silently observing her frustration.
"Need some help?" Kazuki asked, breaking the silence.
Aoi blinked, looking up at him with wide eyes, as though she hadn't realized how tense she was. "Oh, Kazuki… I—uh, yeah. I'm stuck on this math problem. I don't get it at all."
Kazuki chuckled, pushing himself out of his chair. "Alright, let me take a look."
He moved over to her desk, standing behind her and peering down at her notebook. Aoi shuffled a bit, adjusting herself in her seat, clearly aware of how close her brother was. Kazuki ignored the slight tension in the air, focusing on the problem in front of him.
"It's simple," he said, pointing at the equation. "You just need to use the distributive property. You can break it down into smaller parts, like this."
He demonstrated the steps, his voice steady as he explained the process. Aoi watched closely, her gaze fixed on his movements. She was a good student, but she was also a little too proud to ask for help most of the time. Kazuki could tell she appreciated the assistance, even if she didn't admit it.
Aoi's cheeks flushed slightly as she looked up at Kazuki, her voice small. "Thanks… I really didn't get it before. I think I understand it now."
Kazuki smiled at her, feeling a warm sense of accomplishment. He had always been protective of Aoi, but in moments like this, he couldn't help but feel a sense of pride in being able to help her. He knew how hard she worked to keep up, and it meant a lot that she was willing to lean on him for support.
"Don't mention it," Kazuki said, ruffling her hair affectionately. "I'm always here to help, Aoi. Just ask next time, okay?"
Aoi pouted, her face turning a bit redder. "I can do it on my own. I didn't want to bother you."
Kazuki chuckled softly. "You're not bothering me, Aoi. We're family. That's what siblings are for."
Aoi's eyes softened as she looked at him. "You're right… thanks, Kazuki."
Kazuki gave her a knowing smile. "Now, let's finish up the rest of this homework, alright?"
For the next few hours, they worked together. Kazuki explained concepts, patiently walking Aoi through each one until her confidence started to grow. Though Aoi still felt a little embarrassed at times, she couldn't deny that she was glad to have her brother's help.
When they finally finished, Aoi stretched out in her chair, letting out a satisfied sigh. "That wasn't so bad, actually."
Kazuki leaned back, a playful grin on his face. "See? Told you it wasn't so hard."
Aoi narrowed her eyes, her voice teasing. "You're so smug when you're right."
Kazuki chuckled. "It's just because I'm your older brother. It's my job to know everything."
"Right, right," Aoi muttered, her tone softening. "Thanks, Kazuki. I really needed that."
Kazuki gave her a small, reassuring smile. "No problem. Anytime, Aoi."
Aoi stood up from her desk, a sudden thought crossing her mind. "Hey, Kazuki… do you think I could get some help with my chemistry homework too?"
Kazuki laughed, ruffling her hair again. "I'm not doing all of your homework, you know."
Aoi smiled up at him, her expression sweet and innocent, but there was something mischievous in her eyes. "But you'll help, right? I can't do it without you."
Kazuki sighed, knowing full well that he couldn't say no to his little sister. "Alright, alright. Let's get to it then."
As they sat down to tackle another subject, Kazuki felt a sense of contentment. Even though his relationship with Aoi was complicated at times—especially considering how overprotective she could be—it was these quiet moments, these simple acts of care, that made everything worth it.