The word hung between us like a death sentence.
Catalyst.
I'd heard it before, in chemistry classes. A substance that accelerates reactions without being consumed. Something that changes everything around it while remaining unchanged itself.
Except I wasn't remaining unchanged. I was dissolving.
"What does that mean?" My voice came out steadier than I felt. "Catalyst."
Dominic glanced around the library. Two tables over, a student was packing up their laptop. On the other side of the floor, someone's phone buzzed. Normal sounds. Normal life continuing while mine splintered into something unrecognizable.
"Not here," he said quietly. "We need to go somewhere more private. Somewhere I can show you without—" He stopped himself. Closed his notebook with careful precision. "Can you drive?"
"Yes."
"Then follow me. There's a place outside campus. Twenty minutes. I'll text you the address."
"I don't have your number."
Something flickered in his expression—surprise, maybe, that I hadn't saved it from the card he'd given me. He pulled out his phone, typed something. Mine buzzed a second later.
442 Riverside Drive. Blue house, detached garage. Park in back. Come to the side door.
I looked at the address. Then at him. "This is your house."
"It's the only place I can be certain we won't be observed." He started gathering his books. "I wouldn't suggest this if it wasn't necessary. But what you are—what you've done—requires explanations I can't give in public."
Every instinct I had screamed that going to a stranger's house was a terrible idea. That this was how people disappeared. That I should say no, walk away, pretend none of this was happening.
But he was the only person who knew what I was. The only one who could explain why I'd watched my best friend die and then pulled her back from a collapsed timeline.
The only one who might be able to keep me from dissolving.
"Fine," I said. "Twenty minutes."
He nodded. Started to leave, then paused. "Iris. Don't tell anyone where you're going. Don't text anyone the address. Don't—"
"Let anyone know I'm meeting my professor at his house alone at night?" I kept my voice flat. "Already planning on it."
His mouth tightened. "This isn't—I'm not trying to—" He stopped. Started again. "I'm trying to keep you alive. That's all."
"Right," I said. The word tasted bitter.
He left first. I waited five minutes, pretending to work on my laptop, before packing up and heading to my car.
The drive took twenty-three minutes through dark residential streets that got quieter the farther I went from campus. Riverside Drive was exactly what it sounded like—houses backing onto the river, old and expensive, the kind of neighborhood where professors probably couldn't afford to live unless they had family money or no student loans.
The blue house was at the end of a cul-de-sac. Colonial style, well-maintained but not ostentatious. I parked in back like he'd instructed, next to a black sedan that was probably his.
The side door opened before I could knock.
"Come in," Dominic said. "Quickly."
I stepped inside. He locked the door behind me—two locks, I noticed, plus a deadbolt—and led me through a mudroom into the kitchen.
The house was exactly what I'd expected. Clean. Organized. Minimal. Books everywhere, but arranged by some system only he understood. The kitchen was immaculate, like he barely used it. Through a doorway, I could see a living room with leather furniture and more bookshelves.
"Coffee?" he asked.
"I've had enough coffee today to kill a normal person."
"You're not a normal person anymore." He was already pulling out mugs. "And you're going to need it. What I'm about to tell you will take hours."
I watched him move through his kitchen with the efficiency of someone who'd done this thousands of times. Tea for himself—he filled a kettle, selected a tin from a dozen others on the counter. Earl Grey, I noticed. He caught me watching and almost smiled.
"I know. Very predictable." He poured my coffee from a pot that was already made. It was still hot. Like he'd timed it perfectly. "Sit. Please."
I sat at his kitchen table. The chair was uncomfortable in that deliberate way—good posture or nothing. Very professor.
Dominic joined me, tea in hand. He didn't drink it. Just held it, like he needed something to do with his hands.
"Catalyst," I prompted.
He nodded. Set down his mug. "Most Witnesses can only observe. They see timeline splits, probability collapses, deaths and choices playing out across realities. They can't interact with what they see. Can't change anything. They're... passive receivers. Like radios picking up signals."
"But I'm not."
"No. You're not." He leaned back, studying me with those unsettling gray eyes. "Catalysts don't just witness timeline collapses. They cause them. Accelerate them. Create bridges between realities that shouldn't exist. What you did last night—pulling Maya from a death timeline into this one—that's not something normal Witnesses can do. It's not even something most Witnesses would think to try."
"I didn't think. I just—I wanted her back."
"That's the danger." His voice went harder. "Catalysts operate on instinct. On desire. On the fundamental human impulse to fix things, save people, change outcomes. But every intervention has consequences. Maya's alive in this timeline because you pulled her here. But somewhere, something else shifted to balance it."
My stomach dropped. "What do you mean?"
"The universe maintains equilibrium. You can't create life without taking it elsewhere. You can't save someone without someone else paying the cost." He paused. "Someone died last night, Iris. Someone who should have lived. Someone whose death balanced Maya's survival."
The coffee in front of me suddenly looked poisonous. "Who?"
"I don't know yet. That's what I need to investigate. But it's happened. Somewhere in this city, someone's family is grieving a death that shouldn't have occurred. Someone who was alive in the original timeline is now dead in this one. Because you interfered."
I pushed away from the table. Stood. Couldn't sit still with this information. "I didn't know. I didn't mean—"
"It doesn't matter." His voice wasn't cruel, just factual. "Intent is irrelevant. The debt exists. It's been paid. And now the Conclave knows what you are."
"The Conclave?"
"The organization that maintains timeline stability. Ancient Witnesses who've merged their consciousness to monitor and control probability collapses. They're the ones who created the Protocol. The rules. The system that keeps reality from unraveling completely." He stood too, following me as I paced. "And they have zero tolerance for Catalysts."
"Why?"
"Because Catalysts are walking existential threats. You don't just create bridges between timelines—you destabilize the entire structure. One intervention leads to cascading effects across multiple realities. It's like pulling one thread and watching the whole tapestry unravel." He moved to the window, looked out at the dark river beyond. "The last Catalyst the Conclave found was fifteen years ago. A woman named Vera Santos. She tried to save everyone she could. Created so many bridges that reality started fracturing around her. The Conclave ordered her retirement."
"Retirement?"
"Forced dissolution. They scatter your consciousness across every timeline you've touched until nothing coherent remains. It's like being erased from existence while still technically alive. You exist everywhere and nowhere simultaneously. Conscious but fragmented beyond recovery."
My hand found the kitchen counter. Gripped it. In for four, out for six.
"But Vera survived," Dominic continued. "Went into hiding before they could complete the retirement. She's been dissolving slowly for fifteen years, existing on the margins, barely corporeal. A ghost warning other Witnesses away from her mistakes."
"You know her."
"I've met her. Twice. Both times she told me the same thing: if I ever found a Catalyst, I should retire them immediately. Before they could cause the kind of damage she did." He turned back to me. "She told me it would be a mercy."
The kitchen felt too small. Too quiet. The only sound was my breathing and the tick of a clock somewhere I couldn't see.
"Are you going to?" I asked. "Retire me?"
Dominic was quiet for a long moment. When he spoke, his voice was careful. "That's the protocol. What I'm supposed to do. What I've been trained to do. What every Shepherd would do without question."
"But?"
"But I've already lost one Witness to dissolution." Something raw flickered across his face. "My wife. Eliza. She was a normal Witness, not a Catalyst, but she couldn't accept the rules. Couldn't stop trying to save people. I watched her fade over three years. Watched her become translucent, forgettable, until one day she just... wasn't there anymore. Mid-conversation. She disappeared between one word and the next."
He looked at me, and I saw real pain in those gray eyes. Old pain. The kind that never fully heals.
"I won't do that again," he said quietly. "I won't guide someone toward dissolution. Even if the Protocol demands it."
"So what do we do?"
"We keep you hidden. Teach you control. Help you understand what you are so you don't accidentally cause more timeline collapses." He moved closer, his voice intent. "But you have to follow the rules, Iris. Absolutely. No more interventions. No more pulling people between timelines. No matter what you Witness, no matter how badly you want to help—you observe only. Because the next time you interfere, the cascading effects will be worse. And the Conclave will find you."
"How long do I have? Before they find me anyway?"
"I don't know. The fact that you're a Catalyst will show up in probability field distortions. They monitor those constantly. But if you're careful, if you don't Witness frequently, if you absolutely don't interfere—you might have time. Weeks. Maybe months."
"And then?"
"Then we figure out how to hide what you are. Or—" He stopped himself.
"Or what?"
He shook his head. "Nothing. One problem at a time."
I didn't believe him. But I was too exhausted to push.
"Why are you helping me?" The question came out quieter than I intended. "You said yourself—the Protocol says you should retire me. You'd be going against everything you're supposed to do."
Dominic looked at me for a long moment. Something complicated moved through his expression—guilt, determination, something else I couldn't name.
"Because I'm tired of watching people disappear," he said finally. "And because you remind me—" He stopped. Started again. "You asked difficult questions in my office. Challenged my answers. Didn't accept what I told you just because I said it. That's rare. That's valuable. That's worth saving."
"I thought you said you weren't a professor here."
"I'm not. Not in any official capacity. But I audit philosophy classes sometimes. Yours included. You presented your thesis proposal three weeks ago. Professor Chen thought you were being deliberately contrarian. I thought you were asking exactly the right questions."
The idea that he'd been watching me for weeks should have been creepy. Instead, it felt like puzzle pieces clicking together. The sense I'd had in his office that I'd seen him before. That he belonged in places I couldn't quite remember him being.
"So what happens now?" I asked.
"Now I teach you to control your abilities. To sense when a Witness event is coming. To observe without interfering. To maintain your anchor to this timeline." He picked up his tea, finally took a sip. Made a face—it had gone cold. "And you go back to your normal life as much as possible. Classes, thesis, coffee with Maya. The more normal you appear, the less attention you draw."
"How am I supposed to act normal when I know my best friend only exists because someone else died?"
"The same way everyone acts normal while carrying impossible knowledge." His voice was gentle. "You compartmentalize. You focus on what you can control. You accept that some things are unfixable, and you keep living anyway."
It sounded like he was talking about more than just Witnessing.
"When do we start?" I asked.
"Tomorrow. Meet me at my office. Three PM. We'll begin with basic exercises—learning to sense probability fields, understanding your own dissolution markers, recognizing when you're about to Witness." He set down his mug. "For now, go home. Sleep if you can. And Iris—if you start to Witness, if reality begins shifting—"
"Don't interfere. Just observe and call you. I know."
He nodded. "Good. You're learning."
I left through the side door. Drove back to campus through dark streets, my mind racing with impossible information. Catalyst. Conclave. Retirement. Someone died because I saved Maya.
Back in my apartment, I lay on the floor of my bedroom and stared at the ceiling. Tried to process everything. Failed.
My phone buzzed. Maya: You okay? You seemed really off today.
I stared at the text. At the proof that she existed. That she was alive and worried about me and completely unaware that she'd died in another timeline.
I'm okay, I lied. Just tired. Talk tomorrow.
She sent back a heart emoji. Simple. Normal. The kind of thing best friends send each other without thinking.
I wondered who had died so she could send me that heart.
Wondered if I'd ever be able to look at her again without seeing the blood in the parking lot.
Wondered if this was what Dominic meant by learning to live with impossible knowledge.
Sleep didn't come. I lay on the floor counting my breaths—in for four, out for six—and tried not to think about how many timelines existed where Maya was dead and someone else was alive.
Tried not to think about how I'd chosen her without meaning to.
Tried not to think about what that made me.
At 2 AM, my phone lit up with a text from Dominic: You're still awake. I can tell. Stop overthinking. Sleep. Tomorrow is going to be difficult.
I didn't ask how he knew I was awake. Didn't want to know.
Instead, I texted back: Who died? Because of Maya?
Three dots appeared. Disappeared. Appeared again.
Finally: A graduate student named Owen Reese. He was walking home from the library. Heart attack. Twenty-four years old, no history of cardiac issues. It shouldn't have happened.
But it did. Because of me.
Because of choice. Because reality balances. Because the universe doesn't care about fairness. A pause, then: Sleep, Iris. Guilt won't change what happened. It will only make you careless tomorrow.
I put my phone down. Closed my eyes. Tried to sleep.
All I saw was Maya's empty eyes and a stranger named Owen Reese who died so she could live.
All I felt was the weight of being a Catalyst.
All I knew was that nothing would ever be simple again.