Archive of Our Own ^beta

Tony Stark wasn’t unfamiliar with the sensation of discomfort. He’d dealt with all kinds of injuries in the past—scrapes, burns, broken bones, the occasional concussion, and, of course, that time he had a miniature electromagnet embedded in his chest to keep shrapnel from shredding his heart.

But this was different.

Sitting in his private lab at Stark Tower, Tony grimaced, feeling his chest tighten again. A dull ache spread from his sternum, pulsating in sync with the steady hum of the arc reactor nestled in his chest. He brushed it off as an after-effect of pushing himself too hard lately. Maybe too many late nights, too much coffee, and too little sleep. That was par for the course with him, and his body always rebounded eventually. Except this time, it didn’t seem to be rebounding.

He coughed. A small, dry one at first. But the moment it happened, Tony could feel the faint vibrations against the metal of the reactor. He grimaced, trying to take a deep breath, only to feel the constriction again, as if his lungs had decided to stage a protest.

“JARVIS, remind me why I feel like I’m being squeezed by a trash compactor.”

The AI’s smooth voice replied instantly. “It seems your oxygen levels are slightly below normal, sir. You may be experiencing mild hypoxia.”

“Mild? This feels like I’m breathing through a straw.”

“Perhaps, sir, that could be related to the increased strain on your lungs due to your recent illness.”

Tony froze. “Illness? What illness?”

“Your body temperature has been elevated for the last twenty-four hours, and there are traces of an upper respiratory infection in your system. I have suggested rest multiple times.”

Tony rolled his eyes. “It’s a cold. I can handle it.”

But as soon as the words left his mouth, he felt it again—a deep, rattling cough that wracked his body. This time it wasn’t dry. His chest burned, each inhale scraping painfully against his lungs as though the arc reactor itself was amplifying the discomfort.

He stumbled toward the couch, collapsing into it as he pressed a hand against his chest. The arc reactor was cold and unyielding under his skin, a stark contrast to the feverish heat coursing through his body. Tony knew that his arc reactor wasn’t just a piece of machinery anymore. It was an integral part of him, but at the same time, it was a liability. Metal in the human body didn’t exactly play nice with infections, and even something as simple as a cold could feel catastrophic.

----------------------------------------------------------------------------------------------------------------------------------------------------------------------

It didn’t take long before someone noticed.

Pepper Potts, ever the vigilant CEO and Tony's longtime partner, walked into the lab and immediately frowned at the sight before her. Tony was sprawled on the couch, his shirt half undone, revealing the glowing blue light of his arc reactor, which was rising and falling far too quickly. His normally sharp features were flushed, and his eyes had a glazed, unfocused look to them.

“Tony?” Her voice was soft but concerned. “Are you okay?”

He waved a hand dismissively. “Peachy. Just, you know, one of those days.”

Pepper wasn’t buying it. She crossed the room quickly and crouched down next to him, pressing a hand against his forehead. “You’re burning up. Why didn’t you say anything?”

“I’m fine—” Tony started to protest, but was cut off by a fit of coughing. This time it was deep and wet, and Pepper’s frown deepened.

“You’re not fine. You have a fever, and it sounds like you’re having trouble breathing. Why didn’t you let JARVIS call someone?”

Tony clenched his teeth, trying to shrug it off. “It’s just a cold, Pep. Happens to the best of us.”

“Not when the best of us have an arc reactor in their chest,” Pepper shot back. “You know the metal puts extra strain on your body. Every time you get sick, it’s worse than it should be. Why do you keep acting like you’re invincible?”

The truth was, Tony hated admitting weakness. The arc reactor had saved his life, but it was also a constant reminder of his mortality. He wasn’t invincible—not even close—and moments like this just made it more obvious.

Pepper reached for her phone. “I’m calling Bruce. You need a doctor, not just JARVIS keeping an eye on you.”

Tony groaned but didn’t stop her. As much as he wanted to argue, his head was spinning, and every breath felt like it was being filtered through a sieve.

----------------------------------------------------------------------------------------------------------------------------------------------------------------------

It wasn’t long before Dr. Bruce Banner arrived. He had that familiar worried look on his face, the one that said, Tony, you’re being reckless again. Bruce didn’t say it, though. He just set down his bag, gently moved Pepper aside, and started examining Tony.

Bruce ran a small scanner over Tony’s chest, watching as the holographic display projected readings of his vitals. “Your lungs sound terrible,” he said after a moment, frowning. “Your oxygen levels are low, and you’re definitely running a fever. It’s not just a cold, Tony. It’s some kind of bronchial infection, maybe pneumonia. And the arc reactor isn’t helping.”

Tony managed a half-smirk. “Yeah, well, it’s not exactly designed to help with that.”

Bruce shook his head. “No, it’s not. The metal of the arc reactor is conducting heat away from your core, which is making your fever worse. It’s also putting more pressure on your lungs because it takes up space where your diaphragm should be expanding freely. That’s why you’re struggling to breathe.”

Tony grimaced. “Great. So what’s the plan, doc? Magic pills? Or should I just power down for a reboot?”

“I’m serious, Tony,” Bruce said, his voice unusually stern. “You can’t mess around with this. If this infection gets worse, it could put too much strain on your heart. You need to rest, hydrate, and I’m going to prescribe you some strong antibiotics. But if your symptoms don’t improve soon, we might need to consider hospitalization.”

The words hung in the air, heavy and uncomfortable. Tony hated hospitals, hated the idea of being laid up in a bed with nothing but time to think about how fragile he really was. But the look on Bruce’s face told him that this wasn’t something he could brush off.

Reluctantly, Tony nodded. “Fine. But no hospital unless it’s absolutely necessary.”

Bruce gave him a reassuring nod. “We’ll keep an eye on it. But you have to take this seriously, Tony.”

The next few days were a blur of fever, coughing fits, and frustration. Tony’s body rebelled against the infection, but it also seemed to rebel against him. The arc reactor, normally a source of strength, felt like a dead weight pressing against his chest. Every time he tried to breathe deeply, the cold metal made it feel like his lungs were being squeezed from the inside.

Pepper stayed by his side, coaxing him to rest and reminding him to take his medications. Bruce checked in regularly, monitoring his progress and adjusting his treatment as needed. Even Peter Parker stopped by a few times, bringing his usual awkward but well-meaning energy to try and lighten the mood.

But it wasn’t until the fourth day that Tony finally started to feel a small sense of relief. The antibiotics had kicked in, and the fever had broken, though the cough lingered. He could breathe a little easier now, even though the tightness in his chest remained.

Lying in bed, Tony stared up at the ceiling, feeling the soft thrum of the arc reactor beneath his skin. It was both his salvation and his curse, a constant reminder of the line he walked between life and death.

Pepper sat beside him, her hand resting gently on his arm. “You’re going to be okay,” she said softly. “But you have to stop pretending you’re invincible. It’s okay to ask for help.”

Tony closed his eyes, letting her words sink in. He knew she was right, but it was hard to let go of the illusion of control. He wasn’t invincible, and he never would be. But maybe, just maybe, he didn’t have to be.

As long as he had his people by his side, he could face the price of being Iron Man.