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Chapter 1: Discoveries

Tony paced in the medical wing of SHIELD. It was a terrible battle that left Clint, Natasha, and Bruce injured. Clint and Natasha were not that bad and they were sent back to the Tower to rest, but anyone who knew them knew that they were doing the opposite of that. They were not concerning Tony, Bruce was. He was supposed to be indestructible. Nothing was supposed to hurt him. Tony should be able to protect Bruce. Bruce was he little brother, and he was just a baby. Tony knew that he should not be thinking of Bruce this way, not right now. He did not know if Bruce was little and he should not be right now, but he could not help it. He was too scared.

For most of the year Tony and Bruce had been playing together as littles. Tony fell around the age of four or five years old, and Bruce fell around one and a half to two years old. This made Tony Bruce's older brother. That means that he was supposed to protect him. He knew that he could not help that Bruce was trapped under a building after he came back to being Bruce, but he could not help the feeling of guilt pooling deep in his stomach.

The feeling of guilt combined with no one telling him anything made Tony run around the medical unit demanding that someone tell him anything about Bruce. In all honesty he was acting like a dick.

"Tony!" Cap had shouted more that once. "It's no one's fault that Bruce is hurt..." past this Tony refused to listen. He just grumbled under his breath.

Steve was starting to get annoyed by Tony' s actions. Steve knew that Tony was considered about Bruce but so was Steve, but he was not going around acting like a spoiled brat and demanding answers that the staff probably did not have.

"Tony, sit down," Steve said after Tony got done harassing a young, female doctor. As usual Tony just grumbled something under his breath and ignored Steve. That was the straw that broke the camel's back. Not thinking about what he was doing he grasped Tony by the arm, and dragged he to a supply closet. Steve did not care about the eyes that followed them or about how much Tony was struggling.

"Let me go! Let me go!" Tony shouted when they got into the closet. He heard Steve close the door, and fear seeped in and he could not help but whimper. He was then forced over Steve's knee.

"If you don't stop acting like a spoiled brat, I'm going to treat you like one," Steve threatened.

Tony squirmed and he felt tears in eyes, but he could not cry, he had to be brave. For Bruce. When the weight of Steve's threat hit him, Tony's chest heaved and he choked on a sob. He shook his head and felt tears run down his face, "no," he sobbed. "No, n-no, please."

Tony's reaction surprised Steve. Steve expected Tony to curse at him and possibly, if Steve was lucky, sit down and wait for information about Bruce. He did not expect Tony to brake down into tears, begging not to be spanked.

"I- I need to know 'bout Bru. He's just a baby," Tony said as more tears ran down his face. "Babies shouldn't be alone."

"Tony," Steve spoke gently as he put Tony back on his feet, "was are you talking about? Bruce is not a baby, he is 44 years old."

Tony shook his head. He took a deep breath to try and calm himself, and he wiped his eyes and face on his sleeve. He then whispered, as if he was trying to tell a secret, "he's a baby. He's my little brother, 'n' I need to know if he's okay."

Tony did not know why he was admitting all of this, to Steve none the less, but he needed to get out of the closet and see Bruce.

"Tony, how old are you?" It seemed like a dumb question, even as it came out of mouth. He knew Tony' s age, 46, but it seemed like this Tony was decades form the present.

"Four," Tony whispered, looking away form Steve and forcing himself not to stick his fingers in his mouth.

Steve's mind was going a mile a minute, trying to make since of what Tony had just confessed. Tony said that he was a little boy and that Bruce was a baby. What did that mean? They were both grown men in their forties. They could not acutely believe that they were kids. Could they? No, they couldn't. How could they function in society if they did? These questions and meny more ran through Steve's mind as Tony stood in front of him biting his lip and looking completely vulnerable. Tony did look like a little kid when he was acting like this. No, what the hell was he thinking? Tony Stark was an annoying, pain in the butt adult. Sure he acted like a brat sometimes, but an adult. Another thought came to Steve's mind- what if he just played into this, whatever This was. Perhaps if he did that he could get to the bottom of This, and perhaps help the other men.

How they were not questioned about being to the closet Steve has no idea. All He knows that a few minutes after coming out of the closet they were able to see Bruce. The doctor warned them that Bruce needed his rest and might not wake up until tomorrow.

Tony did not care. He just wanted to see Bruce.

When Tony did see Bruce, tears came to his eyes. Bruce's normally tan skin was now deathly pale. The look of his skin was the opposite of the bark blue and black bruises that maps it.

Tony sniffled and slowly walk up to Bruce's bed and sat down on the uncomfortable chair next to the bed. He really wanted to hug Bruce tight and never let go, but he could not do that without possibly hurting Brue more, so he held back on the hugs for later. Steve, for his part just hung back around the entryway as Tony begain to speak in hushed tones to Bruce.

"You're gonna be okay, Bruce. Yeah you're gonna be okay," Tony whispered, so he would not be heard by anyone but Bruce, as he grabbed Bruce's hand and rested his head on Bruce's, hopefully, uninjured shoulder.

Bruce started to stir. "Mmmm," he hummed as he turned his head from the burning lights. Who turned their brightness level on Sun? Bruce wondered. When Bruce tried to move his right hand to shield his eyes he realized that there was a weight in his hand and on his shoulder. He looked down to see messy bark brown hair and knew that it could only be one person, "Bubba."

When Tony heard his nickname he looked up to see Bruce's glassy eyes looking down at him. Tony was so excited to see Bruce awake that he threw caution to the wind and huged his little brother tight.

"Owie," Bruce complained. Hearing this Tony got off of him and bowed his head in apology. "Gentle," Bruce reminded as he opened his arms to receive another hug. Tony gladly complied. This time being much more gentle with Bruce.

While Bruce and Tony were have their little reunion Steve still hung back getting more and more confused. Ten minutes in to the reunion Steve thought that it would be okay to leave them alone, he felt like he was introducing on a private moment, and he felt like he needed to do some research if he was going to understand this.

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Chapter 2: Play Time

When Steve got home he went on his StarkTab only to find articles containing the information he needed to know. How this happened he did not know, but he could make an educated guess that it was one sneaky little AI. None the less, he began to read, and what he read fascinated him. There are grown adults out there who liked to behave and treated as if they were still children or babies. It was something of comfort or stress relief. He supposed that he should be disgusted by this, but the truth was he liked it. He was glad that his teammates have found some stress relief that did not involve blowing something up in the lads. When he looked into it a bit more and found that there was a more... sexual part of this whole thing. This made him blush and hope that this is not what he was dealing with.

After about two hours of research he looked up at the clock and saw that it was twelve A.M. in the morning. Way past his bed time. His friends did not give him the nickname "Sleeping Beauty" for nothing.

Later that morning, with very little sleep under his belt, Steve and the rest of his team went to go pick up Bruce and Tony. When they got to there room they were ment with the, in Steve's opinion, the most adorable sights ever. Tony was in the bed with his thumb in his mouth and with Bruce on his chest. Bruce was clenching Tony' s shirt as if it was a life line, and the hand that was not in his mouth was tangled in Bruce's curls. The thing that relived the young caption the most was the fact that Bruce's color has returned and most of the bruises that he had were faded or completely gone.

Steve was brought back to reality by the sound of giggling and the sound of pictures being taken.

"This is too, cute," Clint cooed and Steve could not decide which was weirder the fact that a master assassin said cute, the fact that a master assassin cooed or the fact that Steve finds this more weird than AgePlay.

Steve was not given long to contemplate that thought as Bruce stated to stir.

"Hmmmm," he hummed like yesterday, "go away," Bruce demanded in a house morning voice as he shifted closer to Tony.

"No can do Doc," Clint said, " We've gotta get you and Snow White home."

Natasha raised her eyebrow at the comparison, "what," Clint said, "she slept too,"

At that moment Tony decided to wake up as well.

"Tony can you convince your boyfriend to get up, so we can go," Natasha said.

"Did you know you suck on your thumb?" Clint asked with a smirk.

After ten minutes of trying to convince Bruce to let go of Tony it took another ten minutes for the man to get out of the SHIELD shirt and pants and into his normal clothes. All the while Tony refused to look at Steve because he remembered last night. He remembers Steve threats to spank him, he remembers braking down and telling him everything, and Tony did not feel like he could face the man ever again.

Well, that is what he would have to do not even a day later.

At adout 11 in the morning Steve stoped by the lad Tony was about to deny the man entry, but Bruce bet him to it by said, "sure let him in." Fuck Bruce.

After Steve came in the air of the room became tense. Tony and Steve locked eyes and Bruce looked confused by the change in the room. He swallowed and said, "do you want anything, Steve?"

Steve tore his eyes away from Tony and looked at Bruce. He noticed how the change affected Bruce, he curled in on himself and looked like he wanted to go hide in a corner. He always looked like this when they first ment and Steve was sad that he made him revert back to that.

"I want to talk," Steve said evenly, as if he was talking to children. "I know about everything."

Bruce's eyes widened in horror, and he looked at Tony," he doesn't mean..." Bruce cut himself off. The look on Tony' s face being the only answer he needed. "You told him," it was not a question but a statement, but Tony nodded anyway.

"I'm not going to hurt you, or anything like that," Steve reassured, but it did nothing to calm Bruce's worry.

Tony glared at Steve. Mad at him because he made Bruce upset. "Then why are you here."

Steve was taken aback by Tony' s angry tone. "I want to help," Steve said trying to defuse Tony' s anger, but it did not seem to work.

Bruce's face turned from horror to hopeful, "you mean..."

Tony cut the younger man off by saying angrily, "we don't want your help!"

"Tony," Bruce tried to calm Tony down, but Tony was too far gone. He was yelling at Steve with pure fury. He could not believe that anyone would want to take care of him or Bruce. It was just too good to be true.

He did not hear Bruce's cries of, "Tony," nor how upset he was making Bruce. The baby looked about two seconds form crying.

Finally Bruce whimpered and shouted, "stop it!" The room went silent only to be filled with the sound of a baby's upset cries a moment later. Steve went into protective mode holding the baby close to his chest, and shushing him.

Tony, on the other hand, felt guilty. He knew that Bruce hated shouting on a good day, but today both of them where feeling little, either being in their little headspaces or in between their little and big headspaces, so Bruce was much more sensitive that normal. Tears entered his own eyes when he saw Bruce burst into tears.

Tony felt his mental age plummet as he said, "I'm sorry, Bru. I'm sorry," Tony came up behind Bruce to give him a hug and unintentionally gave Steve a hug as well.

Not able to stay mad or upset at Tony for too long, Bruce shifted in Steve's arms so that he could take in as much of his brother's love and affection as he could.

When Bruce started to sniffle and calm down Tony noticed two things. One, it was not just him trying to comfort Bruce, Steve was as well. Two, made Steve would be that bad of a caregiver.

"Made we can play later tonight," Steve suggested.

"Yeah," Bruce agreed wiping the reminder of his tears on his sleeve while Tony just nodded.

At 7 at night, both Tony and Bruce showed up to Steve's floor I'm full little gear. Tony had on an Iron Man T-shirt and sweats. Bruce had on a blue long sleeved onesie that said "Little Brother" on it and sweats. Not sure what to do Bruce sat down on the floor with a backpack that Steve did not notice earlier and pull out a box of blocks, "build tower?" Bruce asked looking at Steve.

"Sure, bunny," Steve said as Bruce giggled at the moniker.

Pretty soon the ice was broken and Steve was balancing playing with a baby and an energetic young child who wanted to play with his toy dinosaurs like he had done it all of his life.

Soon their tower was done, "look, look, Bubba look," Bruce said excitedly, bouncing on his butt.

Tony set up a demolition plan that Bruce was, surprisingly, behind. Tony made a catapult out of a long block and two dig cylinder blocks and put a Triceratops on it to fling in at the tower.

The first time Tony did it, it did not work, and Bruce made a sound of disappointment. "I might need a bigger dino," Tony considered.

The second time, however, Tony hit it in just the right spot that the tower fell down. Bruce giggled and clapped his hands. Steve could not help but laugh at how excited the baby was.

Soon both boys were becaming clingy and sleepy. "Are you two ready for bed?" Steve asked.

Tony nodded and said, "Yeah, sleepy."

At 8 the boys were in Steve's guestroom nearly asleep. Bruce was curled up into the fetal position with a red pacifier in his mouth and Tony was on his back, with his arms out, and his thumb in his mouth.

"Steve?" Steve heard Bruce say, shyly.


"Can you sleep here?" Bruce asked with his best puppy dog eyes.

Steve sighed and realized that he would never be able to say no to Baby Bruce, not that he was too good at saying no to Big Bruce.

It took a little rearranging but Steve ended up in the middle with Tony on his side with head on Steve's shoulder. Bruce was still curled up on his side with his head on Steve's chest so he could hear his heart beat. The boys where also holding hands across his chest.

Bruce sighed contentedly, "Night-night, 'addy."

Steve fell asleep with a smile on his face.

Chapter Text


Chapter 3: Of Diapers and Pull-ups

Steve woke up to the sound of whimpering. He looked to his right and saw Bruce with tears streaming down his face and the whimpering noise coming form him.

When Bruce saw that Steve was awake he started crying harder, thinking he was in trouble, "I-I sowwy, S'eve," Bruce sobbed out past his pacifier curling up into an even tighter ball. "I no mean it. I no mean it, Papa,"

"What are you talking about, Bruce?" Steve asked in concern, afraid that his little boy was somehow hurt. He rolled over gently so that he did not disturb Tony. It was then he noticed that there was a large wet spot on the bed and that the air smelled lightly of urine. Bruce had wet the bed in his sleep.

Steve was some what expecting this to happen. He had read somewhere that some littles liked to wear diapers or pull-ups, and with Bruce's "age" being somewhere under two years old he was not surprised that Bruce could not control his bladder completely. What he was surprised, and slightly ashamed, with was that he did not ask the boys if they did wear diapers or not.

"It's okay Brucie," Steve tried to reassure, brushing back Bruce's hair causing him to flinch back. "Hey, it's okay. I'm not mad. You just had an accident. Bruce it's fine," Steve rambled.

"I sowwy, Papa" Bruce apologized with big tears still streaming down his face. He started shaking in fear. The last time he wet the bed his other dad was very mad at him. The bruises lasted for weeks. But Steve would not do that, would he?

"Nothing to be sorry for, Baby," Steve reassured Bruce running his hand through Bruce's hair and pulling him into his chest so that the Baby could hear his heart beat.

" 'S goin' on," Tony asked from behind Steve, his voice laced heavily with sleep. "What's wwong, Bwu," he asked Bruce in concern.

"W-wet," Bruce whimpered out. Looking at Tony with like any little brother would look at his big brother

Tony sat up, "I should have told you," Tony said, rubbing his eyes, "Bruce wears diapers. He just got 'cited late night. He didn't 'member, 'n' I didn't 'mind 'em. I'm sorry," Tony yawned. Steve looked over at the alarm clock on the bed side table, it was 5:47 A.M. in the morning. No wonder Tony still sounded so tried.

Bruce snuggled farther against Steve's chest. "Come on, boys," Steve said picking Bruce up, taking Tony's hand, and leading them out of the room.

"I can go get Bruce's diapers," Tony offered, rubbing Bruce's back.

"Someone could see you, Tony,"

"But no one's up," Tony argued. "I'll be right back," then Tony disappeared into the elevator before Steve could say anything else. Steve was going to have to have a talk to Tony about listening to him.

He heard Bruce whimper and say, "Babba," and felt him tighten the grip he had on Steve shirt.

"He'll be back, Bunny," Steve reassured walking into the bathroom.

He sat Bruce down on the toilet with the lid closed, and turned to turn on the foset. When he did he heard Bruce whimper again. He turned around only to see that Bruce's tears had started again and his pacifier bobbing wildly in his mouth.

"B-but I say sowwy," Bruce cried bringing his knees to his chest and he started shaking. "S'e-Papa, I say sowwy."

"Bruce," Steve said reaching up to run his fingers through Bruce's hair only for Bruce to flinch back. "I'm not going to hurt you. Baby, I'm not mad. You're just a little boy, right, little boys have accidents."

"Th-The bath," Bruce said as he pointed to the tub with a trembling finger.

"Is not a punishment," Steve answered, "I just have to get you all nice and clean. I won't punish you for an accident, Bruce. Ever."

"N-never," Bruce asked with a sad helpfulness in his eyes.

Steve felt his heart brake at the sound of Bruce's voice. He really needed recurrence the he would not get yelled at or hurt by a father figure. "Never," Steve promised. With that one word he was promising to be the best caregiver he could be, to never hurt his boys, and more things. The weight of the promise laid comfortably on Steve's chest.

Steve striped Bruce's nasty clothing off and helped the baby into the bath. Steve started to gently clean the baby. Bruce did not do much aside form sucking on his pacifier and blushing. Bruce was use to having people see him nude, he had to be because of the Hulk, but he was not use to having people wash him. It was not uncomfortable, just new. He could get use to it.

"I'm going to wash your hair, Bunny," Steve warned. Bruce whimpered slightly and shuddered. He hated having his hair and face wet. "Its alright."

Steve quickly washed his hair. After Steve was done Bruce shock his head like a puppy sending little strays of water all over Steve causing him to laugh. "Okay, okay, you little puppy. Stop," he said, gently.

Bruce made a face, scrunching up his nose and making his eyes small. "I not a little puppy," Bruce argued, "I a little bunny."

Steve laughted and said, "that's right, my little Bunny. Come on lets get you out of here, and all nice and dry,"

Bruce nodded and lifted his arm up in the classic 'carry me' position. Just as Steve was drying Bruce's hair Tony came in the bathroom.

"Stop, Papa, stop, pwea'," Bruce begged trying to get Steve to stop torturing him with the towel, it was not working unfortunately.

Steve finally stopped and took the diaper form Tony with a thank you.

"Is Bruce okay now," Tony asked in a childish voice. Looking down at the younger boy with concerned eyes.

"Yeah," Bruce answered letting Steve put his diaper on him.

Knowing that his boys were not going to go back to sleep he went to their room and undressed the bed, gently, as to not get any more pee on himself. He was glad that he had the foresight to put a mistress protector on the bed. Steve then went to his room and put the laundry in the laundry chute. Then he changed out of his dirty clothes and did the same with them.

When he got into the living room he saw Tony helping Bruce into a pair of pants and smiled at how cute his boys looked. Bruce was wearing a caption America onesie and gray pants, and Tony was wearing a plan red and yellow T-shirt. He then noticed that Tony had no pants on and had on a blue, stary pill-up.

He smiled even wider as he realized that he was going to learn even more about his little boys and that he was going to enjoy the ride.

Bruce's eyes lit up when he saw Steve and he said, "Hi, Papa."

Chapter Text


Chapter 4: Tony Time

After lunch the boys were settled down on the couch to watch a movie while Steve cleaned up the kitchen. He made sure that he was in sight of his boys at all times. Over just a day Bruce has gotten really attached to Steve. Calling him Papa and getting a little upset if Steve left his side for too long. He hoped that in the next few times that they do this Bruce will be confident enough that he will not be expecting that Steve will leave every time Steve turns a corner. Tony has also got attached as well, not that he will admit that. He also got a little scared when Steve left the room for long periods of time (5 minutes).

When Steve was done cleaning he came back to the living room and sat next to his boys. He watched as Tony became more and more excited about what was happening on the screen. Bruce, on the other hand, was blinking vary slowly, sucking on his pacifier slowly, and yawning form his set next to Tony. Looked like it was time for baby to have a nap.

"I think it's time for a nap," Steve said ruffling Bruce's hair.

"I'm not tired," Tony whined, immediately, crossing his arms as he pouted slightly.

Steve laughted lightly in amusement and said, "not you, silly boy. Bruce. Unless you wanna."

Tony shook his head as Bruce looked up at the sound of his name, "nap?" the Baby questioned.

"Yep," Steve said then looked at Tony. He looked like he was being entertained by the T.V. once again, Steve swears the kid has ADD. "Are you okay in here while I put Bruce down for a nap?" Steve asked.

Tony shifted in his set, as if he was uncomfortable with the question, or maybe it was Steve leaving him, but he then shrugged and said, "I'll be okay."

"I'll be right back," Steve reassured, picking up Bruce and ruffling Tony's hair. Tony made a face and tried to clean up his hair, only making it worse.

"Night-night, Bubba," Bruce said looking like he was about to pass out in Steve's arms.

Steve walked into the room that the boys and him spent the night before. He laid the baby out on the bed. Bruce instantly tried to curl up on his side to go to sleep, but Steve's hand stoped him.

"Papa," Bruce whined.

"I know you're sleepy, Bruce, but Papa has to change you," Steve explained with a gentle voice.

"No, sleep," Bruce said, shrugging Steve's hand off and curling up.

Steve sighed and rolled his eyes. Bruce might look sweet and innocent, but he could be more stubborn than Tony if he wanted to, "you don't wanna diaper rash, do you?" Steve asked. Bruce tensed slightly and shook his head. He has had one before and never wants one ever again. "Then you have to let Papa change you."

Bruce sighed in defeat uncurling and laying on his back. Bruce watched as Papa get a diaper from out of the closet. He wondered for second when Steve put his diapers in the closet. Steve made fast work of changing the baby's diaper.

The second Steve was done Bruce curled on his side and fell asleep. 

Steve smiled at his baby boy and watched him sleep for a few moments before returning to the sitting room. 

When Steve got back into the living room Tony was still absorbed in the T.V. 

When the movie was over Tony looked at Steve and said, "Steve, I'm bored."

"Oh, no you're bored? What do you want to do?" Steve asked with a soft smile playing on his face. 

"Draw," Tony said. 

Luckily Steve had sketch books and crayons

25 minutes later Tony was finished with his picture. It was extremely good for a child of Tony's "age". It was a picture of Tony, Bruce, and Steve. They were all smiling as if they were in front of a camera. Steve had on a plaid shirt tucked into khaki pants. He was holding Bruce on his hip. Bruce had on a purple onesie and blue jeans. He had a soft, shy smile on his face, and his had his head laying down on Steve's shoulder and his thumb was half way in his mouth. Tony was in a Caption America shirt and black jeans. He had his hand in Steve's and Steve could almost see the sparkle in Tony's eyes.

"This is incredible, Tony," Steve said. His voice was radiating with pride that Tony could not help but left his head up at. Not many people were ever proud of Tony, not even his real father. People normally just expected Tony to do things without any praise or anything, really. So Steve deing proud of him for a simple drawing was same thing Tony was not used to.

"Really," Tony could not help but ask, cocking his head to the side slightly.

Steve gave Tony a sad smile. He was not surprised by Tony's suspension. "Of course." Steve said, standing up, "c'mon let's hang it on the fridge."

Tony followed Steve into the kitchen and hung the picture on the fridge. As if on cue a door closing and Tony did not even have to turn to see was happening. "Bruce 's awake," Tony declared when Steve turned.

And sure enough, the small baby was awake and waddling slowly to word his family. Steve picked Bruce up when he reach them.

"Pwetty," Bruce said in a small voice, pointing at the picture with one hand and rubbing the sleep out of his eyes with the other.

Steve simply smiled in agreement.