A/N: This is the Tony Adopting Peter AU work I mentioned in my one-shot fic. I love this idea and it is my all-time favorite AU for Peter.

I know that I still have Part of the Team going on, and I am working on it, but I decided to start this fic as well because 1) I just had to get this out of my head as soon as I can, 2) I have so many other ideas that are on my list, and 3) I'm trying to write as much as I can during the summer break before my school term starts in the fall, so I have a set schedule for multiple fics.

In terms of the timeline, I am following the years that the movies were released in instead of the official timeline. So Iron Man 2 happened in 2010, The Avengers in 2012, and Iron Man 3 in 2013. (Screw the Homecoming's '8 years later' thing ;p)

Oh, and just so you know, any kind of scientific talk/knowledge used in this is strictly based on internet searches and brief research. I haven't studied science since after my freshman year in high school, so I have to look everything up.

Okay, enough of the babbling, and I'll let you get into the actual fic.

Chapter 01: Responsibility

The incident at the Stark Expo was indeed a catastrophe. Still, despite it having been so disastrous, the event all ended with a rather small number of casualties. There were, of course, civilians that had to suffer injuries and accidental deaths. What was fortunate was that the total number was not too significantly big.

Unfortunately, however, Mr. and Mrs. Parker were among the unlucky ones. May and Ben Parker had brought their eight-year-old nephew Peter, who was a big fan of Tony Stark and Iron Man, to the Expo. The boy was practically running around with excitement and happiness throughout the whole event and it was both guardians' great pleasure to see the boy in such big joy. Everything was great.

That was up until the killer robots suddenly began to fly around attacking people. Being the small boy that he was, Peter was separated from his aunt and uncle in the massive stream of panicking people running and fleeing throughout the site. His guardians were perplexed as they frantically ran around to find their lost boy. They were too distracted by the one and only thought to find Peter to notice large debris falling out of a broken pillar. It took their lives instantly.

Yet, Peter himself did not know such a fact until very later, for he was on his own little moment of panic. The boy was also occupied with finding his guardians when one of the big robots spotted him. It stood firm before him, raising its arm to aim at the small boy. Overcome with fear, there was little Peter could do as he watched it getting ready to kill him. Remembering that he was still wearing the cheap plastic version of the Iron Man mask, he slowly raised his hand. He stretched out his palm, on which he had the plastic Iron Man gauntlet, at the killer drone. He didn't really know what he was doing, to be truthful. Maybe he was trying to trick the drone into thinking that he had the same ability as Iron Man to destroy it. Or he may have been trying to gain courage by imitating his hero. Either way, one thing was certain ― if Iron Man hadn't shown up that very moment to blast the machine completely, Peter would have also been one of the body counts.

Of course, these were all merely small details that Tony did not know; at least not for a few days afterward. The whole AIM drone fiasco took some time to fully clean up afterward. Still, the Stark Expo continued on as was originally planned. The venue was limited for a while, and the people were rather reluctant to return at first, but it did not that long for them to fill the place once again, with a number of companies and industries offering various treats full of new kinds of cutting-edge technologies and products.

Tony, in the meantime, did not return to his home in Malibu. As he had handed his position as the CEO of the company over to Pepper ― and most importantly, now that he had gotten over the whole 'dying' problem ― he had more time to really focus on other things. He stayed in New York so that he could oversee the expo while working on the construction plan for a new tower in the city. He also managed to have some charity works squeezed into his agenda in order to mend the public image of himself and the company.

That was how he found himself in a local orphanage.

The moment he stepped into the facility, Tony was easily surrounded by a pack of people, from little kids to even the fully grown caretakers and other staff members. He was always so used to being swarmed by people, so he had no difficulty in entertaining them. He joked and played around with the kids, gave out autographs on various objects, took pictures, and did many other things he was asked to. And he was truly and literally absent-minded when he casually turned his head to find a small boy watching on from afar. The boy was standing there alone, away from the entire crowd without anyone even noticing him, most likely due to Tony having stolen all the attention.

Then again, Tony was never an ordinary person, which was why he was the only one that spotted the seemingly shy kid. The kid was longingly looking at him as if he couldn't even dare come near the man. That was until Tony's eyes stopped at him. The moment their eyes met, the kid quickly averted his eyes and looked down. Tony's gaze followed toward where the boy was now looking to find a small action figure he was holding in his small hands. And that figure happened to be that of Iron Man.

For some reason unknown, Tony could not take his eyes off of the little boy. It wasn't his first time seeing a young fan. He wasn't the type of person to be self-conscious or embarrassed about the recognition or attention, either; if anything, he enjoyed them. And it wasn't the case that he happened to know the boy. It was definitely the very first time that he was seeing him. Yet, there was just something that grasped Tony's attention and interest instantly. He was so immersed that he didn't even realize that he had been staring at the boy for a while until one of the caretakers spoke softly.

"Oh, that's Peter," she said. Then she looked at the boy to call out to him. "Peter? Why are you standing there, honey? Why don't you come over here and say hello to Mr. Stark?"

Even with the kind voice, Peter just stood still, his eyes looking down and his fingers fidgeting with the Iron Man action figure. In fact, the caretaker's attempt had the opposite effect from its purpose, for the boy seemed to flinch and recoil further into himself. Tony heard the caretaker sigh softly beside him.

"He's a bit shy," she said. "He just came here about a week ago, when he…."

The caretaker so openly hesitated. Something uncomfortably clicked inside Tony's head. A week?

"What exactly happened to him?" He asked. He was already fearing for the answer.

"His guardians― they were his aunt and uncle, from what I've heard. They were, um… they were among the casualties… in the incident last week." The woman slowly finished her sentence cautiously.

Tony's heart dropped immediately. There was no need to ask what incident she was talking about. The guilt and pain that poked at his heart were a sufficient answer in themselves.

"Are there any others that came here from the incident?" Tony asked quietly.

"He is the only one here," she answered. "At least for this facility. And I think I heard that not many were orphaned from that specific day."

Tony quietly took in what she had just said. His eyes remained fixed on the boy. Then he walked over to the boy. He forgot about all the others who had been gathered around him. He didn't care. His eyes were on this one boy, and the boy only. He crouched down in front of him.

"Hey, buddy," Tony offered. He tried to keep his tone casual. "Peter, is it?"

Peter snapped his head up and looked at him with surprise-filled eyes. Yet, he soon lowered his head again as if he avoided Tony's eyes.

"I'm Tony," Tony continued. He honestly did not know what else to say. He had never been good with kids in the first place, and the heavy guilt that weighed in his heart didn't help at all.

"I know," said Peter. It was barely even a whisper, but Tony heard it nonetheless.

And it was a surprise to him, for he wasn't expecting that the boy would respond to him right away.

"You're Tony Stark," said Peter in the same quiet, almost inaudible voice. "You're Iron Man."

"That's right," Tony answered. "And that's me you're holding there."

Peter slowly nodded his head. As if he had become conscious that he was holding the Iron Man action figure just then, he started to play with it. Tony couldn't shake the feeling that the kid was only reacting to Tony's words rather than deciding on his own accords.

That was when it hit hard: Tony was looking at himself. Not the current grown-up version of himself, of course, but his younger self. And it did not mean that he was hallucinating, either. It was just that this little boy named Peter reminded Tony of his own childhood so much. The cautious and hesitant demeanor resembled how he used to be around his father. The lack of speech and the longing behavior were exactly like what he had seen in himself r he had lost his own parents. The way the little boy kept checking on other people's emotions and reactions was what he had to develop from the early years of his life for being thrown into the public eyes all the time.

"How do you know me?" Tony asked, barely managing to keep the choking in his throat under control.

Peter didn't answer right away. He just kept fidgeting his fingers around the cheap-looking action figure. Tony sensed that it was a sign that the boy had something to say. He wondered for a brief second whether he should ask the question again. He quickly decided against it, though, for he didn't want to press the kid. He simply waited.

"I love all the stuff you do," Peter replied eventually. He still refused to look at Tony. "You fight bad guys and help people."

Tony just watched him and waited for the boy to continue. His eyes moved from Peter's face to his fingers, which adjusted the arm of the small Iron Man several times before moving over to the white circle on its chest.

"And the reactor, it's so cool. It powers the entire suit. It's like a battery, but then it should be self-sustainable, it's always stuck on you. And it has to create a lot of energy at once, too, which means there should be endless nuclear reaction going on in it," Peter continued with the same hushed tone, but Tony caught every word he was saying.

He froze as Peter began to talk about the arc reactor.

"I didn't know a reactor could be that small. And it means it's very strong, too, 'cause it powers not only the movement of the suit but the repulsors."

Then Peter gasped abruptly and immediately stopped talking as if he had said something inappropriate. He glimpsed up at Tony with a trace of fear in his eyes and quickly mumbled, "Sorry."

"What for?" Tony asked.

Peter took a moment before answering, "Everyone at my school hates it when I talk about these things. They say I'm weird and annoying."

The tone he spoke in was so calm as if it was just something so ordinary for him.

"Peter," Tony said, unable to hide the shock and seriousness in his voice. "How old are you?"

It took a few seconds before a shy answer returned. "I'm eight."

"Can you tell me everything you know about reactors?" Tony asked in disbelief.

Peter seemed to ponder as if he was unsure if he should answer him.

"It's a kind of a generator, I guess," he replied. "I read in a book that it's about nuclear fission and chain reaction and stuff. I still don't know what it exactly is or how it works and stuff. But I know that it's the nuclear splitting. It's used in power plants for electricity, mostly. It's usually huge, 'cause it needs to cool down 'cause it generates heat so that they can power the turbines to make electricity. Your small one wouldn't do that, I guess, 'cause then you'd die from the heat."

Great. So the kid was a genius. Another common feature he shared with Tony.

And now he had to grow up in an orphanage or random foster homes that are most likely unable to provide adequate opportunities and education for a bright mind like his. Tony could not help the additional guilt weighing down on his heart that it was as if he could feel the physical pain.

Peter must have seen Tony's speechless face. That was probably why he retreated to himself and remained quiet for the rest of the day.

The door of the hotel room opened, and Pepper walked in. She took off her suit jacket while heading to the dresser, walking past the couch where Tony was sitting. He was lost in his thoughts, which Pepper seemed to have not noticed. She casually called out to Tony from her position in front of the vanity as she removed her earrings and bracelet.

"The investigation is almost done," she said. "Finally. Safety checks out, and we'll be able to reopen the venue by the end of next week."

When she didn't hear a reply from Tony, Pepper walked out toward the couch area.

"Tony? Are you listening?"

"I want to adopt the kid," Tony blurted out, standing up.

It was definitely not something the CEO expected to hear from her love. One, it was totally out of context and just came out of nowhere. Two, 'Tony' and 'kid' were not something she knew Tony would like to hear in the same sentence. And three, Tony adopting a kid. Really? So it was logical for her to reply with a deep frown on her face and a surprised "What?"

Tony turned around to face the woman.

"I need to adopt the kid."

"Okay, hold on a minute," Pepper said, raising her two hands as if she was physically stopping him. "What are you talking about? What kid?"

Tony looked into her eyes very seriously as he began to explain.

"There's this kid in the orphanage. He lost his family because of the incident at the expo last week ― because of me."

Pepper's face softened as she realized what was eating at Tony. Although he was infamous for being arrogant, egotistical, and confident, the one thing that really affected him more than anything was guilt. The strong insecurities he always tried so hard not to show were what formed the man he was and also what pressured him. Those were what Pepper saw beneath the mask of the self-centered image he created and what made her care so much about him.

"Tony," she began quietly. "I see what this is about. I understand that you may feel responsible for the kid, but it was an accident. Sure, you were stupid the way you acted around me and the expo for the past few months, but really, I think AIM's to blame, not you."

"That's not the point," Tony cut in.

Pepper shook her head slightly, seemingly trying to talk some sense into him. "If you want to help victimized kids, and we can. And we will. We can create funding programs-"

"No," Tony interrupted, with a violent shake of his head. "You don't understand. I have to― I need to save him."

Pepper stared at the man in front of her. The weight and sincerity in his eyes were real ― too real. She gaped at him without being able to say anything.

"I know I'm asking a lot of you. I know I'm not supposed to decide on something big like this without you, but I need to do this. Please."

Pepper opened her mouth to give an answer but closed it as she couldn't find any words to say. It took a few moments of looking into each other's eyes and her biting her lips until she was finally able to form words.

"I… I can see that you like this kid, but it's adoption we're talking about here," she said. "It's complicated. It's not like shopping for a pet or something. It's an actual adoption. A kid. A human life, Tony."

"I know," Tony replied. "And that's why I need to do it. I can't just leave him at someplace like that. I cannot have his life ruined in some godforsaken childcare system."

"What is so special about this kid?" Pepper asked, quite frustrated. She was not completely certain if Tony could actually be qualified to be a parent. She loved him, sure, but the type of life he led was by no means suitable for having a kid around.

Tony sighed. "He is bright. He's a fucking genius. He is an eight-year-old that knows what an arc reactor is and how it's supposed to work. There is no way he can grow up to his full potential in some governmental childcare system."

"So you want to take in the kid because he's smart?" Pepper concluded. "If it's his intelligence you're worried about, then there are other ways that we can help him."

"No," Tony cut her off, seemingly frustrated and even a little angry. "It's just that―"

He sat back down on the couch with a sigh. Pepper walked around and sat next to him.

"He reminds me too much of me," Tony finished quietly.

Pepper stilled at the revelation. "Tony…."

Tony sighed briefly before he continued. "He just seemed so lost. I saw that look…. The way he acts…. It was all so familiar. And I can't leave him, Pepper. I can't bear to think that he's going to go through the same thing as I did, feel the same pain― the same void. I want to save him from that.

Pepper was truly at a loss of words once again. She looked away from the billionaire, turning her face forward. She bit her lips as she processed the words.

"Are you absolutely sure about this?" She finally asked.

"I'm sure," Tony answered.

"There's no turning back."

"I know."

A moment of silence followed. Pepper looked down at her hands while her brains were busy going through all the legal procedures they needed to go through as well as the necessities of raising a child. Of course, she was not really married to Tony yet, so he would be the only legal guardian for now, but she would have to help along, especially since she was quite sure that she won't be splitting up with Tony in the near future. She sighed softly as she finally made up her mind.

"Alright," she said. "Okay."

There was no answer from Tony. So Pepper continued.

"If you're so sure about this," a pause, "then do it."

Tony looked at Pepper wordlessly. Then he hugged her ― or rather, snuggled into her. Pepper just opened her arms and embraced him, and stayed that way for a while. When they finally broke apart, Pepper said with a smile.

"That kid must be really special."

Tony chuckled. "He really was something."

"I want to meet him. The boy who touched the arrogant Tony Stark's heart." Pepper said mischievously.

Tony replied as he glanced forward, looking quite distant.

"I guess he did."

Getting the paperwork done was the easier part. There was a lot to go through, of course, but it was all just fixed standard procedures. It took nearly two weeks to merely get the basic legal papers done. With Tony having a few strings he could pull with the New York State government, the application part and the evaluation were quite easy. Then came the multiple meetings with the adoption agency, and Tony could easily tell that the interviewers were rather concerned and unwilling to let him adopt anyone. Tony honestly thought that he might not pass the process, but thankfully Pepper had accompanied him to the meetings and managed to persuade them. Also, Tony was quite sincere with the decision and the answers he gave, so it would have been helpful at least a bit.

Considering the special kind of position Tony was in, and the unique connections he had with the government and all, the entire process was significantly shortened. It was a little over a month when all the necessary steps were finally done. All that was left was meeting Peter again to break the news. And Tony had to admit, it was one of the very few nerve-wracking moments in his life. Even after giving a lot of thought to the matter, he would never have been able to be truly prepared for what was about to come.

"It's gonna be fine," Pepper said as she sat next to him in the backseat of the moving car. They were currently on their way to the agency, where they would be having their first official visitation with Peter. "You said so yourself, the boy likes you."

It was true. Peter was definitely a fan of his. But that did not mean that he would automatically want to come live with a total stranger. Being a fan and being a family were two very different matters.

He was trying to become a family with this boy. On an official term. Once the thought dawned on him, he began to wonder if he was being too reckless with the decision. He didn't even know if the boy wanted to be adopted by him in the first place.

"If he doesn't want to be adopted, then we don't adopt him," Pepper said. Tony wondered if she secretly had the ability to read his mind or something. "And we'll find another way to help him.

When the car eventually drove into the parking lot of the agency building, Tony's fear grew even bigger. He and Pepper got out of the car and walked into the building through the back door of it, trying to avoid any and all attention. The last thing Tony wanted was having his adoption (or possibly an attempt at adoption) publicly known and making the child suffer the unwanted attention.

It felt like forever for Tony as he waited in a small meeting room ― which looked more like an interrogation room but just with a brighter color for walls in Tony's opinion. A million thoughts came and went through Tony's mind as he wondered what he would do if the boy were not happy with the idea. What would his own reaction be if that was the case? All the thoughts popped out of his mind with the sound of the door opening.

Along with the female agent that was in charge of Tony's adoption process came in little Peter, and his eyes widened as he spotted the man sitting in the small uncomfortable chair. Tony took a deep breath before quickly throwing a casual smile at the boy.

"Hey, Peter," he offered. "Good to see you again."

Peter looked up at the agent beside him as if he was silently asking if he was in the right room. The agent smiled and led Peter to sit on the opposite side of the table and face Tony and Pepper. She then sat on the chair next to him. Peter looked rather scared and baffled as he sat down. Tony noticed that Peter's fingers were fidgeting as he kept avoiding making eye contact with either of the two adults facing him.

Pepper offered him a warm smile.

"Hi," she said. "You must be Peter."

Peter turned his eyes toward Pepper and slowly nodded.

"Nice to meet you, Peter." Pepper's voice was sweet and gentle. Peter played with his fingers as he replied with a nervous tone.

"N, nice to meet you, too."

He then returned to looking down, just like he did when Tony first saw him in the orphanage.

"Peter," the female agent said. "Mr. Stark and Ms. Potts here have asked to adopt you."

At that, he snapped his head upward and looked at Tony and Pepper with wide eyes.

Tony thought about making a light comment to ease the tension, but something stopped him from doing so. There was a strong feeling in his guts that it was better to just give the boy an affirming gaze instead.

Peter just gaped at him, his eyes blinking. Tony couldn't help but notice how that was the longest time that the boy looked straight at him without averting his eyes. He waited in silence for Peter to show any kind of reaction. When nothing came from the little boy for quite a while, Pepper leaned forward slightly as she cautiously looking at him.

"Peter?" She said. Peter's gaze moved to Pepper. "You don't have to if you don't want it. We don't want to force you for anything. Tony liked you very much on the day he met you and wants you to come with us, but we don't want you to do it if you're not happy with it."

Peter blinked as he just stared at her. All three adults in the room waited patiently as the boy took in what he had just heard. When the boy finally opened his mouth, however, was not something any of them expected to hear.

"Why?" he asked in a barely audible voice.

"I'm sorry?" Pepper asked.

"Why do you want me?"

Pepper looked at the agent, who also met her eyes with a quite surprised and concerned face. She then shared a glance with Tony as well. Peter just kept looking at Pepper.

"Because we want you," Pepper answered, trying to hide the surprise in her voice. "Tony told me how you were such a great boy and he likes you very much. I like you very much, too, and I would be very happy if you were to come with us."

Peter seemed to ponder at her response.

"As she said, Peter, you don't have to do it if you don't want to," the agent said. "We all respect your choice."

Tony's heartbeat began to speed up as he watched the boy silently contemplate on it. He wasn't sure how he should react if Peter refused it. Hell, he wasn't even sure how he should take it if Peter accepted it, either. And the way Peter asked for a reason clearly showed that Peter was probably not into the idea of being adopted. Then again, maybe it was better for both Tony and Peter if the boy turned him down. Tony couldn't help but question if he could really be a loving parent for a child. He may have rushed into this whole adoption process out of impulse, but he wasn't really sure how he was going to become a father.

"What do you say, honey?" The agent's soft voice broke Tony out of his trance. He returned his attention to the boy in front of him. Peter fidgeted a little, looking nervous.

"Can I really come with you?" Peter asked shyly toward Tony.

"Of course, buddy," answered Tony. "That's why I'm here, isn't it?"

"Do you really want to come with us?" Pepper asked.

Peter nodded slowly.

Tony sucked in a breath quietly. He was a bit pleased as if he had passed a kind of a test. Yet, it didn't last long as it was replaced quickly by fear. His heart began to race fast. It wasn't the end. It was only a beginning. And now he was supposed to be a guardian, a parent ― how was he going to pull that off?

A part of him even thought that maybe it would have been better for Peter to have turned him down ― for the both of them. Of course, rejection would have been a little disappointing, but he could have been much more relaxed that he didn't have to hold the responsibility of raising a child. Maybe Pepper was right. Maybe he should have given the matter more thought before he came to a decision in such haste.

Then again, there was no use regretting now. There was no turning back.

The meeting scheduled that day was supposed to be short, and thus ended shortly after Tony and Pepper received Peter's answer. It turned out that Pepper also felt deep sympathy and the need for caring for the kid during the meeting and was up for the adoption more than when she first agreed to go along.

After a month and 3 more meetings later, the nine-year-old boy named Peter Benjamin Parker was officially inducted into the Stark family. Tony insisted that they keep the boy's original surname. It was his way of leaving one last choice for the boy to make after he grew up. And it was for the sake of his privacy as well, for Tony did not want the boy to be swept by the media just for being "his son" now. The one thing he hated the most in his earlier life was constantly having cameras and people swarm him just for being a Stark. That was something he definitely did not want for Peter, especially after having such a hard time of losing his guardians and having to adjust to a new life.

Since Tony was living in a hotel rather than an actual home, Peter had to stay at the orphanage two more months before Tony could wrap all the business he had in New York and leave for Malibu. Tony tried to set up a visitation as often as possible, occasionally bringing him to the hotel room he was staying in to spend some time together. Peter always seemed so quiet and nervous, and it did not improve a lot during the three months Tony saw him. He still did not make much eye contact with Tony and was rather shy. But Tony had not improved that much either, for he was still awkward around him, often unable to find the words to say or uncertain what kind of activity they should do. Then again, Peter did slowly begin to talk more, so Tony saw that as a sign of hope. It was a great relief that Pepper was there to help him along. Whenever Tony didn't know what to do, Pepper was there to the rescue, and Tony was sure that she was the biggest factor that helped Peter relax a little more, although not much. By the time the additional two months were up, Peter called them 'Mr. Tony' and 'Ms. Pepper'.

During the two months, Tony had also arranged through JARVIS to set up a room for Peter in his mansion in Malibu. He left all the specific things and details for Peter to choose later, but had the basic furniture to be ready so that he could use them right away.

The day Peter was to be picked up finally arrived. Despite wanting to pick him up himself, Tony had Happy to go to the facility to pick the boy up, for he wanted to make everything discreet and out of the media's watch. He headed to the airport instead, where he had a private plane waiting for him and the newest member of his family. Pepper was there as well, but she was to stay in New York a little longer to take care of some company business before she returned to the Western coast.

Tony waited by the stairs toward the door of the plane, until the familiar black car drove through the airfield and stopped in front of him. Happy got out of the driver's seat and opened the car door so that Peter could step out of the car. Happy, having been the driver to bring Peter over to Tony's hotel, was also quite familiar with the boy by now. He was neither highly supportive or against Tony's decision to adopt Peter. Still, he was always quite gentle toward him - maybe not so overly caring, but just soft enough for the kid not to feel so tense.

The boy was holding a backpack tightly with his hands. Pepper smiled at the sight. Then he and Happy walked over toward Tony and Pepper.

"Hi, Peter," she said.

"Hi, Ms. Pepper," replied Peter, ever so timidly.

"You ready?" Tony asked. Peter nodded slowly.

Tony awkwardly offered a hand toward Peter. Peter looked at it and then up at Tony. Then a short moment later, he slowly raised his hand to hold it.

And together, the two of them walked up the stairs and into the plane.

A/N: I have to warn you, it's going to be quite a slow process for Tony and Peter to actually form a Father-Son relationship. There would be fluffs but also a lot of angst. Both of them are too insecure with themselves and they're gonna suffer for it.

I'm kinda worried if Tony was too out of his character, but I decided that he needed some really deep emotional reasons to actually have a reason to want to adopt Peter. I'm sorry if you didn't like it... But I thought it was necessary. I'm not really sure about Peter's speech about the reactor either. He is a genius kid, but then I'm not a genius nor very familiar with anything scientific, so if it seems inappropriate for his age/intelligence, I am sorry…

The ending also kinda feels rushed. I had to summarize a lot of things so that I could actually move onto the new life of Peter and Tony. Also, I thought it would be too lengthy and drag on too much if I wrote all the small details out. I might edit that part a bit later on.

I'd love to know what you thought! Feel free to tell me in the comments below :)

Always, thank you for reading my fic(s) and I hope you all have a great day!