The afternoon found them scattered through the ruined building like leaves after a storm.
Elias had taken Ren to check the upper floors, teaching the boy how to assess structural integrity - what sounds to listen for, what cracks to watch, what signs meant a ceiling was about to give way. It was practical knowledge, the kind that kept people alive, and Ren absorbed it with the quiet intensity of someone who had learned that information was survival.
Gray had retreated to a corner of the laundromat with a scavenged notebook and a pen that barely worked, trying to organize his thoughts into something coherent. The Proof Codex was still just a name, a concept, but he was determined to give it substance. Every observation he'd made about the mana - the cold-water sensation, the threads, the way intent shaped response - went onto the page in his cramped, careful handwriting.
Mina found him there an hour later, her presence announced by the soft scuff of her boots against concrete. She settled beside him without asking permission, her back against the wall, her hands wrapped around a bottle of water she wasn't drinking.
For a long moment, neither of them spoke. The silence between them was comfortable, the kind that came from shared experience, from having survived together through things that didn't need words.
Then Mina said, quietly, "I feel it too."
Gray looked up from his notebook. Her voice was soft, almost hesitant, and there was something in her expression that he couldn't quite read. Vulnerability, maybe. Or exhaustion. Or both.
"The mana," she continued, her gaze fixed on the water bottle in her hands. "When I heal. It's like pulling something from myself and giving it to someone else. It leaves me empty."
Gray set down his pen, giving her his full attention. He'd suspected something like this - had seen the shadows under her eyes, the tremor in her hands after she'd healed him, the way she sometimes seemed to fade at the edges after using her abilities. But hearing her say it aloud made it real in a way that observation alone couldn't.
"Tell me," he said simply. "What does it feel like?"
Mina was quiet for a moment, gathering her thoughts. The wrong-color light from outside painted her features in shades of amber, highlighting the fatigue that seemed permanently etched into her face.
"It starts as warmth," she said slowly, feeling her way through the description. "Here." She pressed a hand to her chest, just below her collarbone. "Like something is building up, gathering. When I touch someone who's hurt, who's wrong inside, I can feel the wrongness. It's like... a bruise. A note that's out of tune. A knot that needs to be untied."
She paused, her fingers tightening around the water bottle. "And then I push. I don't know how else to describe it. I take that warmth, that gathering, and I push it toward the wrongness. And it... flows. Out of me, into them. Fixing what's broken. Making the note right again."
"But it costs you," Gray said. It wasn't a question.
Mina nodded, her expression tightening. "Every time. The warmth leaves, and something else goes with it. Something I don't know how to name. Energy, maybe. Or strength. Or... something deeper." Her voice dropped to barely a whisper. "Sometimes I wonder if it's pieces of myself. If every time I heal someone, I'm giving away a little more of who I am."
Gray studied her face - the shadows under her eyes, the faint tremor in her fingers, the way she held herself like someone bracing against a cold wind. He thought about his own experiments with the mana, the headaches that followed, the sense that he was pushing against limits he didn't understand.
"You shouldn't push yourself so hard," he said quietly.
Mina smiled, small and tired. "You shouldn't either."
He had no response to that. She was right, of course. He'd been experimenting with the mana every chance he got, pushing against the boundaries of what he could do, ignoring the headaches and the exhaustion because the discoveries felt too important to stop. He couldn't tell her to be careful without being a hypocrite.
"I've been trying to understand it," he admitted instead. "The mana. How it works, what it responds to. I've made some progress - I can make things vibrate, sometimes, if I focus hard enough. But I don't understand the cost. Why it hurts. Why it takes something from us."
"Maybe that's just the nature of it," Mina suggested. "Maybe using mana always costs something. Maybe that's the price of changing the world."
Gray considered this. It aligned with what he'd observed - the headaches, the exhaustion, the sense that he was depleting something every time he pushed the mana. But it also raised questions that he didn't have answers to.
"If there's a cost," he said slowly, thinking aloud, "then there must be a way to measure it. To understand what we're paying, and how much we have to give. Otherwise we're just... guessing. Hoping we don't give too much."
"Like the people in the hospital." Mina's voice was hollow. "The ones who gave everything and still couldn't save anyone."
Gray remembered the bodies they'd found, the desperate attempts at healing that had ended in death for both the healers and the ones they'd tried to save. People who had pushed too hard, who hadn't known their limits, who had burned themselves out trying to do the impossible.
"We need to understand this," he said, more to himself than to Mina. "Not just for us - for everyone who can use mana. If there are others out there, others who are discovering what they can do, they need to know the risks. They need to know how to protect themselves."
Mina was quiet for a long moment, her gaze distant. Then she said, "When I heal you - when I healed your shoulder - I felt something strange. Not just the warmth leaving me, but something else. A... connection. Like our threads were touching."
Gray's pattern-sight flared instinctively, reaching for Mina's thread. It was there, as it always was - a gentle, flowing pattern that seemed to pulse with the rhythm of her breathing. But now that she mentioned it, he could see something else. A faint resonance between her thread and his, a harmony that hadn't been there before.
"I see it," he said, his voice hushed with wonder. "Our threads - they're aligned somehow. Not the same, but... complementary. Like they recognize each other."
"Is that because I healed you?" Mina asked. "Or was it always there?"
"I don't know." Gray shook his head, frustrated by his own ignorance. "I've only been seeing the threads for a few days. I don't have enough data to know what's normal and what's not."
He pulled the notebook toward him, flipping to a blank page. "We need to document this. Everything you're describing - the warmth, the transfer, the cost, the connection between threads. It's all data. All pieces of the puzzle."
Mina watched him write, her expression thoughtful. "You really believe this will help? Writing everything down?"
"I don't know if it will help," Gray admitted. "But I know that not writing it down guarantees we'll forget. Or misunderstand. Or make mistakes that could have been avoided." He looked up at her, meeting her eyes. "Elias says understanding mana is the difference between survival and extinction. I think he's right. And I think you're part of that understanding, Mina. Your healing, your perceptions - they're data points. Evidence. Pieces of the truth that we need to see the whole picture."
Mina was silent for a moment, something shifting in her expression. Then she nodded, almost to herself, and some of the tension in her shoulders eased.
"I'll tell you everything I can remember," she said. "Every time I've healed someone, every time I've felt the mana move through me. Maybe there's a pattern there. Maybe it'll help you understand."
"It'll help all of us understand," Gray corrected gently. "This isn't just my project, Mina. It's ours. Yours, mine, Elias's, Ren's. Whatever we're building, we're building it together."
The words hung in the air between them, heavy with implication. Mina looked at him for a long moment, her hazel eyes searching his face for something. Then she smiled - a real smile this time, small but genuine.
"Together," she repeated, as if testing the weight of the word. "I like that."
---
They sat together for another hour, Mina describing her experiences with healing while Gray recorded everything in his cramped handwriting. The warmth that built in her chest. The sense of wrongness she felt in injured bodies. The way the mana flowed from her to them, carrying something of herself with it. The exhaustion that followed, the emptiness, the slow recovery that never quite brought her back to full.
Gray asked questions, probed for details, tried to find patterns in her descriptions. He was building a picture, piece by piece, of how healing mana worked - or at least how it worked for Mina. Whether it would be the same for others, whether there were variations and exceptions, remained to be seen.
But it was a start. A foundation. The beginning of understanding.
By the time Elias and Ren returned from their inspection of the upper floors, Gray had filled three pages with notes. His hand ached from writing, and his head throbbed faintly from the concentration, but there was satisfaction in the work. In the progress. In the sense that they were moving forward, even if the destination was still unclear.
Mina had fallen asleep against the wall, her water bottle still clutched in her hands, her breathing soft and even. Gray watched her for a moment, noting the shadows under her eyes, the faint lines of exhaustion around her mouth. She was giving too much. Pushing too hard. But so was he. So were all of them.
That was the nature of survival now. You gave what you had, and hoped it would be enough.
Elias caught his eye from across the room, raising an eyebrow in silent question. Gray nodded toward the notebook, then toward Mina, trying to convey what had happened without waking her.
Elias understood. He always understood. He moved quietly to Gray's side, glanced at the notes, and gave a small nod of approval.
"Good work," he murmured, his voice barely audible. "We'll talk more tonight. After she's rested."
Gray nodded, closing the notebook and tucking it into his jacket. The Proof Codex was growing, page by page, observation by observation. It wasn't much yet - just a collection of fragments, pieces of a puzzle they didn't fully understand.
But it was something. And in a world that had taken so much away, something was worth holding onto.