"The inevitability of change might be a universal constant."

*

The library was precisely 2.3 decibels quieter than Sheldon Cooper had anticipated. He was midway through his regular Friday routine: reading, note-taking, and silently lamenting humanity's sluggish pace in solving physics' greatest mysteries—when an unmistakable voice broke his concentration.

"Wow. Of all the libraries in the world..."

Sheldon's hand froze mid-scribble. He didn't need to look up to confirm it. That voice, laced with a biting edge he remembered all too well, could only belong to one person.

"Paige Swanson," he said, without so much as turning his head. "The probability of running into you again was highly improbable."

"Nice to see you too, Sheldon," Paige replied, plopping into the chair across from him without waiting for an invitation. She set a battered notebook and a coffee cup on the table, the latter dangerously close to his meticulously aligned papers. He flinched but said nothing—for now.

"MIT didn't teach you about personal boundaries, I see," he remarked, eyeing her with the same mix of disdain and curiosity he'd had when they were kids.

She smirked. "Dropped out before they got to that part of the syllabus."

His pen stilled completely. "You dropped out?" His voice rose slightly, incredulous. "But you were... well, you were second only to me in terms of intellect and potential. What could have possibly compelled you to abandon your education?"

Paige leaned back in her chair, crossing her arms. "Oh, you know. Existential dread. Crushing imposter syndrome. The fun stuff."

Sheldon blinked. "That doesn't sound fun at all."

"It's called sarcasm, Sheldon."

"I'm familiar with sarcasm," he replied, his tone defensive. "I'm simply pointing out that your choice seems illogical. You were on a path to achieve greatness, albeit slightly below my level. Why would you forfeit that?"

Paige stared at him, her expression unreadable. "Because, Sheldon, not all of us thrive under the pressure of being 'gifted.' Some of us crack."

He frowned, tilting his head. "I've never cracked."

"Yeah, no kidding," she muttered. "You're like a robot in a bowtie."

Sheldon's hand reflexively went to straighten his nonexistent bowtie. "I prefer the term 'resilient.'"

Paige huffed a laugh, though there was little humor in it. "Of course you do. You've always had this... tunnel vision. You don't get distracted by feelings, or... or the constant nagging fear that you're not good enough, that you'll never live up to what people expect of you."

Sheldon opened his mouth to respond, but Paige cut him off. "And before you say it, yes, I know that's irrational. Doesn't make it less real."

He shut his mouth, suddenly uncertain. Paige had always been his intellectual rival, a constant challenge to his superiority. But now, sitting across from him, she seemed... diminished. Frayed at the edges. It made him uncomfortable in a way he couldn't quite articulate.

"Well," he said finally, "it seems to me that you've allowed external factors to cloud your judgment. If you'd simply ignored societal pressures and focused on your work—"

"I didn't come here for a lecture, Sheldon," she snapped, her voice sharp enough to cut him off mid-sentence. "I came here to study. Or at least to try. So if you're just going to sit there and dissect my life choices, maybe I should—"

"... I missed you."

The words left his mouth before he'd even fully processed them. Paige froze, her eyes widening slightly as she stared at him.

Sheldon cleared his throat, suddenly very interested in aligning the edge of his papers with the table. "What I meant was... our conversations were stimulating. You were one of the few people who could keep up with me intellectually. And... well, I haven't encountered anyone quite like you since."

Paige blinked, the anger in her expression softening into something more vulnerable. "Sheldon..."

He looked up, meeting her gaze. "It's a statistical rarity to find someone who truly understands you. Even if that person is occasionally irritating and prone to underachieving."

"Gee, thanks," she muttered, though there was a hint of a smile tugging at her lips.

"I'm serious," he said, his tone uncharacteristically earnest. "You may perceive yourself as a failure, but that's an emotional conclusion, not a logical one. By my calculations, your potential remains significant, provided you're willing to apply yourself."

Paige laughed softly, shaking her head. "You really don't know how to give a compliment, do you?"

"I thought I just did," he replied, frowning. "Did I not?"

She shrugged. "Close enough."

They sat in silence for a moment, the weight of unspoken history hanging between them. Paige sipped her coffee, her eyes flickering toward the window.

"You know," she said finally, her voice quieter now, "I used to hate you."

Sheldon raised an eyebrow. "That seems counterproductive."

"I hated that you were so... sure of yourself," she continued, ignoring him. "You never doubted that you belonged, that you were special. Meanwhile, I was constantly second-guessing everything. I felt like... like I was just pretending to be smart. Like any minute, someone was going to figure out I was a fraud."

Sheldon frowned. "That's absurd. You were never a fraud. Your intelligence was evident in our many debates, even if your conclusions were occasionally flawed."

Paige smiled faintly. "High praise."

"I'm being sincere," he said, his tone unusually gentle. "You are remarkable, Paige. You always have been."

Her smile faded slightly, and she looked down at her hands. "Thanks, Sheldon," she murmured. "That... means a lot."

Another silence settled between them, but this one felt lighter, less fraught. Paige glanced at her watch and sighed. "I should go. Got a deadline looming."

Sheldon nodded, though he felt a strange pang of disappointment. "Very well. It was... enjoyable to see you again."

"Yeah," she said, standing and slinging her bag over her shoulder. "You too."

As she walked away, Sheldon found himself watching her go, a flicker of something unfamiliar stirring in his chest. Regret, perhaps? Or simply the recognition of a bond he hadn't fully appreciated until now.

Either way, he knew one thing for certain: the world would be less interesting without Paige Swanson in it.