So this idea came from a tumblr post that I saw at some point and forgot who made it, and then I did a little research (though not enough that this is 100% medically accurate). Still, I hope you enjoy.

Breathe In, Breathe Out

When Tony opened his eyes, it was to a dark room. Blinking and struggling to adjust to the darkness, he took stock. He'd been kidnapped once or twice, enough to know how it felt. It felt like this. Like full-body soreness and the dizziness that came with a probable concussion. Like blurry vision and cold and a hope that Rhodey rescued him so he wouldn't have to build another suit out of scraps to fight his way out. It tended to freak Pepper out when he got kidnapped, so he hoped his old friend showed up sooner rather than later, and then he would take her on a vacation. Maybe out to a really nice dinner. He'd apologize. Promise to be more careful. And he would be.

If he never had to wake up on the floor of a cold cell again it would be too soon.

Flinching at the pain in his back as he sat up, Tony got his knees under him, then steadied himself on the wall. He wasn't injured, thankfully, but he was ready to get the hell out of there and into his own bed, preferably with a bubbly water and plate of good sushi from that place he liked. Or maybe one of those sandwiches from that corner deli that that kid always brought him.

The kid.

Peter.

Tony jumped to his feet, spinning in circles until he saw it...the body crumped in the corner. "Shit...shit, shit, Peter," he hissed, hurrying over to the boy and dropping to his knees once more. "Peter?" he asked, shaking him a little, not daring to move him more than that.

He'd been picking Peter up from school. Academic Decathlon. And then...then his memory was a blank. But that didn't matter. What mattred was making sure Peter was okay and getting them the hell out. Screw waiting for Rhodey. He had Spider-Man with him. Peter could punch his way through a brick wall. But first he had to wake up. "Pete? Come on, kid. Eyes open. We're kind of in a pickle here and I'm going to need your help to get out of it. Come on, Pete. You're the Amazing Spider-Man, right?"

He was rambling. He knew he was rambling. But he needed Peter to wake up, and not just because the kid was strong and capable and always ready to help. He needed to see that Peter was okay. He needed to see for himself that the kind was fine. Relatively unharmed. Judging from the blood on the back of his head, the kid probably had a matching concussion, but otherwise, he didn't see any marks on him. He could have been drugged, but his breathing was deep and even. Tony pressed his fingers against Peter's throat, then sighed in relief when the boy stirred, one of his fingers twitching, then his nose. After a second, his eyes shut tight, then fluttered open as he stared up at Tony in apparent confusion.

"Mr. Stark?"

"That's my name. Well, Anthony. Tony to my friends. Mr. Stark to you, but that's only because you're insanely polite."

"My dad...he told me to call old people by their last names."

"I'll bet he did, you little brat," Tony told him with a fond smile that he felt stretching across his face. "How's the head?"

"Hurts."

"That would be the concussion."

"Makes sense." Peter nodded, pressing one hand against the floor, and Tony slipped a hand under his shoulder and carefully helped him sit up. "Where are we?"

"Kidnapped," Tony told him shortly. "Haven't seen our actual kidnappers yet, but considering we're in a cell…" He shrugged, trying to feign lightness.

"So you were waiting for me to wake up so that I could rescue you."

Tony rolled his eyes. "More like I was waiting for you to wake up so I wouldn't have to carry you out of here when I inevitably get us out of here."

Peter laughed, the sound making Tony's shoulders relax a little, despite the way the kid flinched and pressed a hand to his head. The hand came away bloody and Peter sighed, wiping it absently on his jeans. "This sucks. I'm starving. Think we can get mexican food for dinner?"

"We can get anything you want, kiddo."

"Oh...that changes things. How about...steak?"

"Sure."

"Ribs?"

"Sounds good."

"Really fancy fish?"

"Surf and turf. I like it."

Peter giggled, grinning at Tony in the dark, and he reached out, wrapping an arm around the boy's shoulders and resting his head on Peter's when the kid leaned against him. But the comfort didn't last long. Peter stiffened suddenly, and Tony removed the arm, turning to follow his gaze as two men, both wearing ski masks, stepped into view outside of their cell. Shifting a little away from Peter, Tony crossed his arms.

"Thank you for agreeing to meet with us. How can we help you?" He could practically feel Peter smirking beside him and congratulated himself on at least keeping the kid's spirits up. The boy had never been kidnapped before. Tony wanted to make this the only time.

Their kidnappers, however, didn't seem to find him amusing. Which seemed to be par for the course for kidnappers. No sense of humor. "We have a proposition for you, Tony Stark."

"Of course you do."

"We want you to make us an arc reactor."

Tony sighed. Right. "I hate to tell you this, but I don't negotiate with terrorists."

"Is that your final answer."

Tony hesitated, not daring to look over at Peter. These men were too calm. Something was wrong. "I'm not making weapons for terrorists. I wouldn't do it in Afghanistan and I'm not going to do it here."

The man who had been speaking nodded. "I understand. We all have our moral codes. But perhaps we can persuade you."

Before Tony could ask what that meant, the second man moved so quickly it was as though he was a blur. There was a noise. A bang, so loud that Tony's ear's rang. And from his side, a short, pained cry, and Peter was thrown back against the wall. "Peter!" he screamed, lunging to catch the boy before he dropped. His t-shirt blossomed with blood right over his right shoulder, and the boy met his gaze with huge, pained eyes before he tried to force a smile.

"I'm okay...I'm…"

"We'll give you a few hours," the leader interrupted before he was walking away, leaving them alone in the dark cell once more.

The bullet was still in him. Tony had nothing to get it out. Peter was bleeding. His face was pale and afraid and it was Tony's fault they were there. But he was going to be okay. It wasn't a fatal shot. It was some blood loss and it would require surgery but it was going to be okay. "You're okay," he murmured, ripping Peter's shirt open, then pulling his own jacket off and pressing part of it to Peter's shoulder. "You're definitely getting that surf and turf now."

"How about…" Peter gritted his teeth. "Sushi? Like, good sushi. Not the gas station kind."

"You eat gas station sushi? Geez, kid. It's a wonder you've made it this long."

Peter gave him a pained smile, closing his eyes and taking deep breaths. "You...you can't do it."

Tony paused.

"You can't make it for them. No matter what."

"Pete…"

"No matter what they do to me. Please. Don't do it. They'll hurt more people."

"I know, Pete. I'm not going to make anything for them. I promise."

It was a promise that tasted like ash, his heart skipping a beat at the thought. No matter what they did to Peter. No matter what.

They came back in three hours. Three hours of Tony pressing his coat to Peter's shoulder and knowing that they'd have to cut him open to get that bullet out. Three hours of talking to keep himself awake through the dizziness and three hours of hoping that Rhodey found them soon. At one point, Tony asked if he could break through the bars...maybe get them out of this quietly. He was fine with sneaking out and living to fight another day, but Peter shook his head.

"Electrified bars," the kid muttered, tapping his ear. "I can hear them. He shut them off right before he asked you to make the arc reactor."

When the leader returned, there were six of them, all with huge guns at their sides. The leader stepped forward again, and Tony moved in front of Peter. "I'm going to kill you," he told them softly, matter of factly, all pretense forgotten. "You hurt my kid, I…"

"Mr. Stark, will you cooperate and make the arc reactor for us? If you agree to do so, you have my word that we will release both you and your son upon completion."

Tony closed his eyes, jaw clenched. They were going to hurt Peter if he didn't. Torture him. Maybe shoot him again. And he wanted to say yes. Because for Peter he'd do it. For Peter, he'd at least pretend to do it. But how long could he pretend? And what kind of message would that send to the world? Threaten Peter Parker and Tony would do whatever you wanted? What's worse, it was true. Tony would do anything to protect Peter.

Only...he'd promised Peter that he wouldn't do it.

Tony took a deep breath. Tried to collect himself. "Look, if you let us go now, I'll work with you. The Avengers are on their way right now, so if you let us go, I'll make sure they go easy on you."

"The Avengers are on their way?" the leader asked.

"Should be here any minute," Tony bluffed.

The man nodded slowly, then gestured toward the other men who drew their guns, pointed them into the cell and right at Tony and Peter. "Then I suppose we don't have much time as I'd hoped. Let's go."

Two of the men stepped into the cell, guns pointed right at them, and Tony lifted his hands, watching as Peter did the same in his peripheral vision. One man grabbed Peter by his arm, and another grabbed Tony, pulling the two of them to their feet in tandem. Together, they were led out of the cell and down a long hallway, all the time surrounded by guns pointed at their heads. Tony knew the boy was aching to run...to break away and fight. But the kid wouldn't risk him getting shot.

The room they were led into had a cell in one corner, and in the middle of the cell, a hole in the floor with an open hatch door. Tony frowned, glancing over at Peter who didn't seem to understand any better than he did. They were led into the cell, along with three of the gunmen and the leader who took Peter's arm and led him, almost gently, over to the square in the floor which, upon closer inspection, was some kind of underground tank filled with what Tony assumed was water.

"Mr. Stark. This is your final chance. Will you build the arc reactor for us?"

Tony's heart was racing but the boy shook his head, giving him something like a comforting smile.

"I can…" Tony took a deep breath. "I can get you immunity. If you let us go…"

The leader's eyes softened a little, and he sighed. "Alright, Mr. Stark." The man turned to Peter, leaning in close and whispering something Tony couldn't make out. Pater's brows drew together, and he opened his mouth as if to ask a question. But then, the man shoved the boy, and as if in slow motion, Peter dropped into the tank of water.

Before Tony could step forward, the leader kicked the hatch with the sole of his foot, the metal door closing with a deafening clank, and then the click of a lock.

It took Tony almost three whole seconds to scream. To lunge forward. "No! No! Let him out! Let him out!"

"I'm sorry, Mr. Stark. I believe we'll give you some time to think over your position."

The men backed away as Tony threw himself to the ground, grabbing at the handle and pulling with every ounce of strength. But the door held fast. "Let him out! Let him out!" he screamed, the force of it making his throat ache as the tears sprang to his eyes and began to fall down his cheeks, his breath coming too fast and too hard but the door wouldn't open!

"Peter! Peter! Let him out!"

The men were gone and he was alone and he could hear the faint tapping against the door from underneath and he could imagine the boy in the water, surrounded by darkness. He would be scared. Peter hated small spaces. He hated the dark. Ever since the warehouse and the Vulture...he would be scared. "Peter! No...no no...Peter!"

Tony knew that when you died, your life was supposed to flash before your eyes. But as he knelt beside the hatch door, he hands scrabbling uselessly at the metal, he saw Peter's from the moment he met him...from the moment he first saw him on that screen in his lab to the afternoon in his apartment, when Peter stepped into the living room and met his eyes, earbuds in his ears, a hood over his head. The first time he appeared in the suit that Tony had made him, fighting Captain America like it was no big deal. Rescuing him from the river. The ferry. The bridge. Peter turning down his offer to join the Avengers.

Tony slammed his fist against the metal over and over again, feeling his fingers break and bleed and not caring. Then lab days and movie nights and dinners together in the tower with Pepper. Texts during class and meetings and laughter and love and this was his son! Peter was like his son! He couldn't lose his son. Not now. Not Peter.

"Please!" He screamed until his voice was hoarse and then he screamed some more but there was no more tapping on the underside of the door. "Please! I'll do it! I'll make it! Let him out! Let him out!"

He beat on the hatch until his hands refused to lift and until his screams had turned to sobs and all he could do was lay atop of the hatch and shake and beg in a whisper, over and over, please, let him out please, please let him out. I'll do it, I'll build it, I'll build anything. Please. He stopped counting.

He stopped keeping track of the time. He knew. It had been so long. Too long.

He'd never known pain like this.

The explosion shook the building. The screams of their kidnappers, which would have been music to his ears, barely registered. And then Rhodey was racing into the cell, followed by Steve Rogers. Steve! Steve was strong! It was a manic, hopeful, desperate thought. Steve was strong...almost as strong as Peter.

Rhodey started to speak to him in that soft, careful voice he reserved for when Tony was falling apart or freaking out but Tony couldn't focus on them. "Tony! Hey, man, you're…"

"Steve!" he cried, voice so hoarse it was unrecognizable. "Get him out. Please...please get him out!" He didn't care that Steve had betrayed him for Bucky. Didn't care that he was technically a war criminal. If he just saved Peter, all would be forgiven. He'd get him pardoned. He'd give him the tower and the compound. He just had to save Peter!

The man knelt beside him and Tony pulled himself upright on his knees, tapping a bloody hand desperately on the locked hatch. "Tony…" Steve started, but Rhodey got it first, skin paling.

"Tones, is Peter in there?"

"You have to get him out! Please! He's scared...he doesn't like small spaces and…and he's been down there for so long..." his voice broke off and Rhodey moved to his side, supporting him and holding him up as Steve gripped the handle and pulled, groaning with effort before finally snapping the door off.

Both he and Rhodey froze when they saw what was down there. Water. "Tony...oh...god, Tony…" Rhodey whispered, shaking his head and gripping his shoulders.

"No! No you have to get him out!" Tony lunged for the water but Rhodey held him fast.

"Tony," he whispered, voice full of anguish that broke Tony as he crumpled against his friend. "I'm sorry. God, Tones...I'm so sorry…"

"Get him out! Please! Please, he's scared! Get him out!"

Steve met his gaze, jaw clenched, then gave a sharp nod as he knelt over the tank and reached a hand down into the liquid, peering into the darkness. It wasn't long before he seemed to find something, then he put both of his hands into the water and pulled a pale, almost translucent Peter out, laying the limp body onto the concrete floor. Tony lunged for him, yanking away from Rhodey, and neither man stopped him, averting their eyes as Tony knelt over the boy and touched his cold cheek.

"Oh god...Peter...you're okay. It's okay. I've got you."

"Tones..." Rhodey started, a hand resting on his back, but Tony ignored him. He had to give him rescue breaths. Had to get him breathing. He was fine. He had to be fine. This was Peter. Spider-Man. Peter Parker couldn't be dead.

"We're going to get you warmed up, buddy. Then we're going to get you that steak you wanted," he murmured, then pinched Peter's nose, pressing his mouth over the boy's and giving two quick, hard breaths while Steve and Rhodey sat back, exchanging glancing and looking sick. Tony placed his bloody, broken hands together over the boy's chest and pressed hard, not caring when he heard a rib snap and not caring when his fingers screamed in agony. It didn't matter. As long as Petr was alive, it didn't matter.

Rhodey gripped his shoulder again, as if to pull him away. "Tony, buddy...I'm sorry. I'm so sorry. I know you love him. But he's..."

And then Peter's whole body jerked, mouth opening and the water spilling out as he choked and tried to gasp for air.

"What the fuck…" Rhodey whispered, but Steve was faster, gripping Peter's shoulders and rolling him over on his side, patting his back firmly as Peter gasped for air, his whole body starting to shake.

"Tony...how long did you say he was in there?" Rhodey asked in a whisper.

"An hour...or more. It was...it had to be an hour," Tony whispered, reaching for the boy with hands that refused to grip him...refused to pull him up to Tony's chest, so he leaned over instead.

Peter's eyes fluttered open, and he looked up at Tony, water and tears running down his cheeks. "Mr. Stark?" he rsped, the sound painful and scratchy.

"Peter? I'm going to help you sit up so I can get you out of that shirt, okay? We have to get you warmed up." Steve pulled the boy upright, and once Tony was supporting him, Steve grabbed the hem of the boy's t-shirt and pulled it over his head, then yanked his own shirt off and gently wrestled Peter's arms into it.

"Peter...hey, look at me," Tony urged, feeling his shattered mind trying to pull itself back together. The boy's wet hair fell limply into his pale face, and the kid's lips were blue, whether from cold or a lack of oxygen, Tony didn't know. "You're okay. I've got you. You're okay. We're going home."

"I…" Peter coughed, pressing a hand to his chest and shuddering. "I could breathe it. But it hurt. My chest hurts."

Tony nodded as if that made sense, wrapping his arms around the boy and running a bloody hand through his damp hair. "Rhodey, we need a sample of that liquid."

Rhodey nodded, and Steve got an arm around Peter's other side, he and Tony working together to pull a shaking Peter to his feet. He managed two steps, then his legs buckled under him, and Steve scooped him up, patting him on the arm. "You're okay, son. We're getting you both to the medbay. Just stay awake for me, okay?"

"Okay," Peter agreed in a rasp, eyes searching for Tony who made sure to stay in his line of sight, ignoring the agony in his fingers that refused to straighten. That was going to need surgery he thought with a dull smile before his legs too buckled, and Rhodey grabbed his waist, supporting him as they hurried toward the jet.

Helen would give him an explanation of the liquid...perfluorocarbon. Oxygenated liquid. Not ideal to breathe for over an hour, but Steve got him on oxygen the moment they got onto the jet, and Tony stayed right at his side, resting his head on Peter's shoulder as Rhodey worked to bandage his hands. He didn't care, though. He didn't care that his hands would need surgery, or that he would have to help Peter deal with what could be a lifelong phobia of water. All he cared about was that his boy was alive.

For now, that would be enough.