Chapter Text
When Tony wakes up, Bruce isn't there. He looks across at Pepper, who has her fingers entangled with his over the empty space where Bruce had been sleeping between them, and wonders how he even managed to get away. Tony carefully removes his fingers so as to not wake Pepper and sits up in a mild state of panic when it hits him that Bruce could be anywhere. He's so small and fragile and who knows how much trouble he could have already gotten into. Or worse - how much trouble someone else could be putting him in while he is young and vulnerable.
"Shit, shit, shit," Tony mutters under his breath as he gets out of bed, pulls on a t-shirt and jeans, and hurries out of the room.
He checks the room next door, but Bruce is nowhere to be found. He heads to the kitchen and finds it empty as well. The lab is next, and when he enters it he calls, "Bruce?"
"Oh- um, hi, Tony," Bruce replies, turning around to wave shyly at him from where he's standing by the window, still in his pajamas.
"Oh, thank god you're here," Tony sighs in relief. "You shouldn't disappear like that, you scared me."
"I'm sorry," Bruce says, looking sheepishly at the ground as his fingers play with the edge of his shirt. "I- I didn't mean to scare you. I just wanted to check on the lima beans."
"It's okay, Bruce," Tony says, relaxing as he meets Bruce by the window. "How are they doing?"
"They grew!" Bruce says excitedly as he holds up one of the cups, which houses beans with tiny green tendrils peeking out of them. "Look, Tony, they sprouted."
"That's great, Bruce!" Tony congratulates him with a wide grin. "Mine never even got that far. I over-watered them, I think."
"Over-watered?" Bruce repeats worriedly. "I'll only water them a little, then."
"Well you don't want them to get too dry, either," Tony reminds him. "How about you water them a little bit now, and then later you come back and give them some more? That way they'll have time to absorb."
Bruce nods very seriously. "Okay, I'll do that."
He switches the cup he's holding for the other, and looks inside it disapprovingly before holding it out to Tony.
"This one's yours. It didn't grow as much as mine did, but don't worry. I'll make sure it lives."
Tony laughs. "Okay, Bruce. I trust you."
Bruce places the cup next to its fellow on the windowsill, then turns around again. "Tony?"
"Yeah?"
"How does photosynthesis work?"
Tony quirks an eyebrow, shrugging. "Eh, air, water, sunlight, et cetera. I can't remember all the details, it's too early in the morning for thinking."
"That's what they tell me at school," Bruce says, frustrated. "There's got to be more to it than just a bunch of ingredients. Isn't this experiment supposed to teach me how it works?"
"The experiment doesn't teach you, it just shows you. If you were in school then your teacher would explain it."
"Can you be my teacher?" Bruce asks promptly.
"I wouldn't make a very good teacher," Tony responds, running a hand through his hair. "Besides, Biology's boring."
"I like Biology," objects Bruce, and then balls his hands into fists at his sides and grumbles,"I want to learn about it, but father won't let me read any smart books."
Tony's quiet for a moment at that, then he says: "Hey, I have an idea! Why don't you ask JAVIS to be your teacher? He knows everything about everything."
Bruce brightens immediately at the suggestion. "JARVIS, can you teach me about photosynthesis?"
"Of course, Master Banner."
Tony smiles, proud of his AI's efficient adaptability and functionality. He's already realized that the former Dr. Banner is no longer a doctor and has changed his name on his own. He listens to JARVIS' detailed explanation of the process for a while without really hearing anything that he's saying. He needs coffee before his brain will function correctly, and he decides to slip away and go get some while Bruce is occupied with JARVIS' lesson.
Pepper is lured into the kitchen by the smell of coffee brewing. She finds Tony drinking out of a mug by the coffee maker and takes a cup of her own.
"Where's Bruce?" she asks as she stirs in some creme.
"He's in the lab, learning about photosynthesis from JARVIS," Tony explains between large gulps of coffee.
"Eager to learn," Pepper observes with a nod, "That's good."
They drink together for a few more minutes before Pepper has to leave to get dressed for work.
"You'll be fine taking care of Bruce all day, right?" she asks.
"If I could handle him yesterday, I can handle him today," Tony replies confidently.
"Good luck," Pepper says anyway, giving him a quick peck on the lips before heading out. She tastes like coffee, which makes Tony suddenly crave it again and he refills his mug before heading back to the lab to check on Bruce.
Bruce is sitting in a chair when Tony returns, staring attentively at a holographic model of a plant cell that JARVIS has conjured up for him to inspect.
“Hey, how’s the lesson going?” Tony asks, placing his coffee down on the table and stepping back to look at the hologram with Bruce.
“It’s great!” Bruce says with a big smile. “Look, Tony, this is a plant cell, it has a cell wall and chloroplasts and everything!”
“That’s neat. Did you know you can touch these holograms?” Tony asks. Bruce shakes his head and Tony leans past him to pick up the cell easily. Bruce’s mouth opens in a gasp and he demands eagerly, “Teach me!”
Tony shows him how to manipulate it in his hands, first placing the hologram into Bruce’s open palms and letting him look at it from all angles before showing him how to select and grab it from the interface himself.
Eventually JARVIS announces that Selvig has arrived and Tony tells the AI to let him in. The door opens instantly and Selvig walks in, dressed in a casual button-down and slacks and carrying a case that is presumably full of his own lab equipment.
"Dr. Selvig!" Tony exclaims with a grin as he turns to see him. Bruce accidentally drops the holographic plant cell in surprise, his eyes wide as he looks at the newcomer.
"Mr. Stark!" Selvig replies, laughing, as Tony walks up to shake his hand. "Is that my old colleague over there?"
"Not so old anymore," Tony quips as he nods. Selvig releases his hand and walks over to the table where Bruce is sitting.
"Bruce Banner?" Selvig asks, bending his knees slightly to get down to the kid's level. He holds out a hand, and Bruce glances over at Tony for approval - which he receives in a smile and a nod - before shaking hands with the doctor.
"I'm Dr. Selvig," he explains, "I'm going to be running a couple of tests on you today, but don't worry, it's nothing serious."
"Am I sick?" Bruce asks, confused.
"No, no," Selvig says, "I'm not even a medical doctor, so I'm not looking for any kind of sickness. We've just got to take some of your blood and see what kinds of chemicals you've got inside you."
Bruce doesn't seem convinced at all, but he glances over at Tony again.
"It's alright Bruce. How about we find you some clothes while Selvig gets all set up?"
"Okay."
Bruce hops off the chair and takes Tony's hand. JARVIS makes the plant cell model vanish into thin air, and Selvig opens his case onto the table in its stead.
Tony takes Bruce to the guest room where they had thought he'd be staying before he'd decided to take up residence between Pepper and Tony. He knows Pepper put all of the clothes she bought Bruce there, and conveniently finds them in the first dresser drawer he opens.
"Aha," he says, pulling out the shirt on the top of the folded stack inside and holding it up to see that it's - an Iron Man shirt?
"Did Pepper buy you this, Bruce?" Tony asks, dumbfounded.
"Yes," Bruce says as he fiddles with the edge of his pajama shirt again, "I think she said you'd like it."
"Of course she did." Tony glares at the red and gold t-shirt, which is designed to look like the front of the Iron Man suit itself. Bruce doesn't know who Iron Man is, let alone that Tony is Iron Man. Pepper had clearly bought it just to mess with Tony. He sighs once before giving up and handing the shirt over to Bruce and finding him a pair of jeans to wear with it.
Bruce changes into the day clothes and, after pulling on the shirt, looks down to run his fingers over the design, stopping when he hits the pale blue circle on his chest.
"Hey, Tony," he says, "This looks like the arc reactor."
"Uh, yeah, it kinda does," Tony says with a shrug.
"That's weird," Bruce mutters, clearly confused by the similarity.
"Yeah, it's pretty weird. But, hey, now we match," Tony says with a smile, taking Bruce's hand again and heading back to the lab.
Selvig is waiting for them when they return. He's brought with him the necessary tools to draw blood from Bruce and has everything already sanitized and ready for use.
"Hey, Bruce," Selvig says with a smile, "Are you ready?"
Bruce eyes the hypodermic needle on the table and shrinks back slightly, swallowing hard. After a moment's hesitation, he looks up at Tony.
"Can Tony do it?" he asks.
Tony looks over at Selvig, who shrugs. "It doesn't matter who takes it, I just need it," Selvig chuckles, "Tony, do you know how?"
"Sure, yeah, I've taken blood before." He turns to Bruce. "Go sit down, buddy, I'll do it."
Bruce looks a lot less nervous as he settles into the large chair. Tony strides past him to examine all the venipuncture tools that Selvig has laid out.
"You're going to want to protect yourself, just in case," Selvig tells him quietly as he hands him a pair of safety gloves. Tony waves them away and shakes his head.
"I've got my own."
Tony and Bruce - when they were both adults - had done quite a lot to keep the lab and its inhabitants healthy and gamma-free. They installed radiation sensors all over the lab and created, among many other safeguards, gamma-resistant gloves. They were appropriately green in color and went all the way up to Tony's elbows as he pulled them on.
"Did you make those?" Selvig asks, examining the flexible green material.
"We did," Tony replies.
"Have you done this before?" Selvig asks.
"I have," Tony says, and he anticipates the follow-up question before it is asked. "He made me destroy all the samples, so you can't see them, sorry. But JARVIS kept all the data, just ask him about it."
Selvig smiles. "Perfect. We'll have something to compare our new sample to. JARVIS? Get me the data on all previous Bruce Banner blood samples..."
Tony turns to Bruce as Selvig crosses the room. He's got a stethoscope and a sphygmomanometer in one hand and a tray with the needle and vacutainer in the other. Bruce is busy tracing the lines of the Iron Man suit design on his shirt when Tony pulls up a chair next to him. He looks up at Tony, adjusting his glasses slightly and tilting his head. "Are we starting?"
"Yep. I'm just gonna take your blood pressure first," Tony explains, placing all his tools on the table beside him before picking up the ones he needs.
"Which arm do you want me to do it on?" Tony asks.
"Umm... My left," Bruce decides, holding it out after a bit of consideration. Tony nods and slides his chair closer to wrap the cuff around the boy's thin upper arm and slide the stethoscope beneath it. He begins inflating the cuff, watching Bruce's face to make sure he isn't causing him any unnecessary discomfort.
"Dr. Selvig is okay with you using all of his doctor stuff?" Bruce asks over the sound of air puffing into the cuff, a crease of worry forming on his brow.
"Of course. I'm no doctor but I know how to take care of some tools. Don't worry about it."
"JARVIS thought I was a doctor," Bruce tells Tony. "When I woke up here. He said Dr. Banner."
Tony nods. "He was confused," he says, then chuckles, "We all were."
He starts releasing air from the cuff, focusing on the sound of Bruce's blood flowing in his artery and telling JARVIS to keep track of the data as he speaks it out to him. He removes the cuff shortly afterward and places it aside, pulling the stethoscope out of his ears to let it rest around his neck. Bruce prods at the end of the stethoscope and asks, "Can I hold it?"
"Sure, buddy," Tony says, pulling it off his neck and handing it to Bruce. He turns to the table to get the tourniquet and alcohol wipes, and when he looks back Bruce is wearing the stethoscope and Tony grins because it reminds him of older Bruce Banner, playing doctor for real in third world countries.
Bruce sees Tony's grin and smiles back, giggling as he touches the end of the stethoscope to the front of his shirt and says, "I'm listening to the arc reactor."
Tony laughs and reaches for Bruce's arm to tie the tourniquet. "The arc reactor actually just makes a sort of humming sound. Pepper says it's soothing. You can listen to the real deal when we're done taking your blood, if you want."
"Okay," Bruce says with a small smile that quickly twitches into a frown at the tightness of the tourniquet. “Is this going to hurt?”
“Uh... no,” Tony tries, searching with his eyes for a vein in Bruce’s outstretched arm. Bruce looks at him, a small smile on his lips. “You’re bad at lying.”
“Okay, fine,” Tony chuckles, “It’ll hurt a tiny bit when it goes in, but that’s it. After it’s in you can barely feel it, I promise.”
Bruce nods, apparently believing him this time, and bites his lip a bit as Tony rubs the alcohol wipe over his exposed vein. The needle goes in a second later, and Bruce flinches slightly but keeps his arm still under Tony’s green-gloved fingertips..
“See? That didn’t hurt, right?” Tony asks Bruce as dark blood starts to pour into the vacutainer.
“N-No,” Bruce says, but Tony can see his free hand squeezing the end of the stethoscope as it rests against his stomach.
“Just relax,” Tony says softly, “It’ll be over soon.”
He fills a second vacutainer before carefully sliding the needle out of Bruce’s arm and immediately pressing a cotton ball to the oozing speck of blood left behind.
“All done. Look, you get a purple bandage ‘cause it’s the only one we have,” Tony says with a smirk as he wraps the medical bandage around Bruce’s elbow, securing the cotton ball in place.
Bruce watches him apply a bit of pressure to the spot and asks, “Will testing my blood help me get home?”
“I hope so,” Tony says, turning away after a moment to dispose of the now-toxic needle safely.
“I don’t even know how I got here,” Bruce says, frustration tightening his tone as he picks at the itchy edges of the bandage, “I just woke up in your lab.”
Tony walks back over to him and sits down again. “Bruce, we’ll get you back home. I promise. Don’t worry about it.” He pauses for a second, then points to the stethoscope around Bruce’s neck. “Want to listen to the arc reactor or not?”
Bruce’s preoccupied look transforms into a smile as he nods. He pulls the stethoscope up to his ears and reaches out to place the chestpiece in the center of Tony’s arc reactor, which can be seen glowing through his shirt even in the daylight of the lab.
“It does hum,” Bruce observes, smiling widely at Tony. As he says it, Selvig returns, wearing his own pair of green gloves, and picks up the filled vacutainers to test them.
“Interested in the arc reactor?” Selvig asks Bruce conversationally as he holds up one of the vials of blood to the light. “Marvelous piece of tech. I’d love to know more about it, too.”
“There’s one on my shirt,” Bruce pipes up as he takes off the stethoscope and puts it on the table.
Selvig looks over and smiles. “Yes, it’s a nice Iron Man shirt. Mr. Stark gave it to you, I presume?”
“No,” Tony huffs, “Pepper did.”
“What’s Iron Man?” Bruce asks.
“Uh,” Tony says, “A movie.”
“There’s a movie about the arc reactor?”
“No...” Tony trails off, trying to think of a way out of the conversation.
Bruce frowns. “Are you lying again?”
“Hey, why don’t you go check on the plants? You can probably water them again now,” Tony suggests quickly.
“Okay...” Bruce agrees, but Tony can tell that he’s still suspicious as he gets up and walks over to the window, still picking at the purple bandage.
Selvig has JARVIS test the blood samples and compare them to the previous data. As they wait for the results, Tony texts Steve to see how the search for the cure is going, not in the mood to actually call and talk to him.
anything yet? -TS
The reply comes promptly.
We think we’ve located the perpetrator. Some kind of mad scientist. We’re planning our attack right now. We should have them in custody and working on a cure soon. -SR
Tony sighs.
i wish i was out there helping instead of just babysitting -TS
You are helping, Tony, by taking care of Bruce. He needs you. Maybe now more than ever. -SR
Tony looks at that last text for a long moment. He needs you...
Seconds later, JARVIS interrupts with the results of the test.
“I’m not sure if it’s good or bad news, sir, but the level of gamma radiation in Master Banner’s blood is the same as it was before.”
“So the Hulk is still here,” Tony states in wonder. He imagines what the Hulk would look like right now - scrawny and small, probably half Tony’s size. Hopefully Tony will never have to see him. If he can keep Bruce happy, the mini-Hulk will be making no unwanted appearances - not that Tony needs any more incentive to make Bruce’s short stay with them a good one. Now that he knows a cure would arrive within a day, he’s determined to make sure Bruce is happy, as happy as he can make him, before he’s sent back to live his shitty life. He knows Bruce won’t remember any of it - he’s been shrunken, not sent back in time - but Tony can’t help but want to show Bruce that there is still happiness in store for him, a future where he’s wanted and cared for and loved. Maybe that’s what Steve meant.
“He is indeed,” Selvig agrees, breaking Tony out of his reverie. “His mutation stayed with him even through his age-change. Whenever the rest of the Avengers find the cure, he should change right back into the Bruce you know, green guy and all.”
Selvig seems happy about the news. Tony knows it’s a blessing and a curse and that Bruce will think the same. The Hulk is here to stay.
Tony and Selvig analyze the results a bit more, telling JARVIS to take notes in case the teams needs more data to make the cure. Eventually they get to cleaning up the area, packing away all of Selvig’s things. Tony thanks him for coming as he heads out and Selvig says he was happy to help. Just as Tony’s about to take off his gamma-gloves, Bruce approaches him, holding his left arm out and away from his body.
“Tony?” he says, “It’s bleeding.”
Tony spots the dark blood seeping out from under the purple bandage and grimaces. “I’ll get you more bandages. Don’t pick at them this time.”
Bruce nods, the look of a guilty puppy on his face. He gets back into the chair and Tony cleans up the trickle of blood with a sterile wipe before removing the old bandage and fixing him with a new one. As he applies pressure to the spot, hoping to staunch the bloodflow completely this time.
“Did you get blood anywhere else?” Tony asks suddenly, realizing how dangerous that could be.
“I don’t think so,” Bruce replies, sensing the worry in Tony’s voice and biting his lip. “Am I in trouble?”
“No, don’t worry about it. I’m pretty sure there’s nothing you could do that would get you in trouble with me.” Tony grins, and Bruce smiles back, relieved. “Want to work on the robot again?”
Bruce’s smile widens. “Definitely!”
Pepper returns to the tower later that evening to find her entrance to the lab barred by a curious robot that looks something like a tech'd out thermostat. It has a little red blinking light on it and it's refusing to open the door for her without a password.
"Password," it states again when she doesn't answer the first time out of shock. Its voice sounds almost like a juvenile version of JARVIS'.
So this is what Tony and Bruce have been working on.
"You've got to be kidding me," Pepper grumbles. She tries to find a way around it but it's wired into the electronic lock on the door and there's no way to get it open manually. Eventually she gives in and humours the robot. "Um, password... Science?"
"Password incorrect," the robot tells her, and then repeats, "Password."
"You have terrible manners," Pepper clucks, "JARVIS would have at least said 'please'."
"It is just a rudimentary security robot, ma'am," JARVIS supplies, apparently trying to give Tony and Bruce some credit.
Pepper rolls her eyes. "Can you get me in?"
"Of course, Miss Potts."
There's a second of silence before the robot's light suddenly blinks green and the lock clicks open. She walks in the door and her jaw drops immediately at the sight of what's inside.
Tony and Bruce have turned the entire lab into a pillow fort.
Pepper's speechless as she approaches what she presumes is the entrance to the labyrinth they've created by draping the tables with sheets and standing up pillows in all shapes and sizes to make walls. There's a paper flag standing in the center of it all, bearing the words "Science Fort" messily scribbled in crayon. Before she can reach the tunnel facing her, Tony pops out of it and gasps dramatically.
"Bruce! She found out the password!"
Bruce crawls out after him and smiles up at Pepper, not at all as shocked as Tony. "Hi, Pepper!"
She waves to Bruce and watches in amused disbelief as Tony gets to his feet and brushes off his jeans.
"Actually, I didn't have to guess the password. JARVIS opened the door for me," she explains.
"That, my dear, is called cheating," Tony complains, but leans in for a kiss anyway. As soon as they part, Bruce tugs on Tony's leg.
"Can I tell her the password?" he asks, smiling up at Pepper, who leans down to kiss him on the head at the same time.
"No way!" Tony scoffs. "It's a secret fort, Bruce, remember?"
Bruce looks from Pepper to Tony, clearly conflicted. "But I like Pepper."
"You can't just go around giving out the password to everyone you like, Bruce, that kinda defeats the purpose..."
Pepper rolls her eyes. "I'm starting to forget who the five-year-old is, Tony."
Tony sticks his tongue out at her, gets down on his knees again, and crawls back into the fort. Bruce makes a move to follow, but changes his mind and turns back to Pepper to quickly whisper, "The password is 'lima beans'!"
Pepper laughs and Bruce tugs on her hand, motioning for her to come along. Pepper can't stop herself from following her boys into the fort on all fours. She's never seen a smile like that on Bruce's face before and she's not about to turn it into a frown.
The three of them eat dinner together again like a family. This time they order Chinese and store the leftovers in the fridge for another day. While Bruce gets ready for bed, Pepper and Tony converse outside the door.
“An Iron Man shirt? Seriously?” Tony says, shaking his head.
“It was just so cute,” Pepper giggles, “If you wanted him to wear something different you should have bought him the clothes yourself.”
“What else did you get him? A Captain America shirt?”
“No, no. You’ll see what else I got him tomorrow. Speaking of Steve, did you talk to him at all today?”
“Texted. They’ve almost found a cure.”
As the realization hits her, her voice falters. “So tonight could already be our last night with him.”
Tony shrugs. “Could be. Yeah, probably. But it’s not like he’ll be gone. He’ll just be... bigger. The Bruce we remember instead of the one we’ve come to know.”
Bruce exits the bathroom a minute later, teeth brushed and ready to sleep. He goes straight to their room with them to curl between them like he had the night before, and falls asleep almost instantly in the soft glow of the arc reactor. As Pepper runs her hand through his curls, she whispers over to Tony, “You can’t tell me you won’t miss him, like this.”
Tony thinks back to the beans, the robot, the fort, the overwhelming but exhilarating feeling of being the protector of someone so vulnerable and small.
“You’re right. I will.”