Izuku sat up and sighed. He thought that this time he'd managed to correctly lock away Fa Jin and the moments of intuition that had been pulling his focus. He had spent all night trying to get it right in the vestiges' throne room. Some of the vestiges, namely Yoichi and Shinomori, had thought it was a bad idea and that he should embrace any power he's given, but the others had not voiced their own thoughts, so it was easy to drown them out. He clenched his fists and paused for a moment. Day four of winter break was upon them and they still hadn't found anything. Izuku was not going back to school without having contributed. He had been led around by his nose by his own power the whole time, but he'd thought he'd done it when One for All had guided him toward that house on the hill. It turned out to be Yoichi recognising his childhood home and nothing more, so that was embarrassing for Izuku. He just wanted to be useful and regain Aizawa's trust. Why could he not do that?
All Might came around and told Izuku what the plan was. Apparently, searching themselves was useless with such a small party and with skills and abilities so unused to reconnaissance, so they were switching tactics. They were all going to go down to the police station and review construction records to see if any structures had been built in town that had secret additions or rooms that couldn't be accessed normally, or simply any buildings that had no construction records. Tsukauchi was supposedly confident about this angle, as it was a large factor in how they caught All for One the first time he and All MIght fought, the time they'd beaten each other to the brink of death. That didn't exactly get Izuku fired up and ready to go, but he got out of bed and got dressed in his costume without complaint.
The drive over was silent and painful, at least for Izuku. He knew they had to be disappointed. He could feel Gran Torino staring at him through the rear-view mirror, though he refused to look and confirm it. Izuku knew they had to be tired of getting nowhere, but did they blame him? He had wasted time on that house on the hill, so it was partially his fault. But was that fair? He was trying, at least, and that was what counted, right? He remembered something Ochako had said a long time ago, right after the first round of internships. Heroes sometimes have this mindset of all or nothing. Sometimes it's good to just try something, even if it doesn't work.
Izuku focused on that sentiment, and was able to stop himself from spiralling into a panic attack in complete silence. He suspected that it wouldn't be anywhere close to the last time he wished she was there with him, just because she was usually the one that levelled him out when he was stuck in his own head and worrying about something that wasn't as complicated as he was making it. Remembering that saying of hers was able to get him to a place of clearer thinking, though, and he figured that if anything, the adults around him were probably blaming themselves for this investigation hitting a dead end. After all, they were all veterans in the field, so how were these Nomu evading them so completely? Izuku decided that he was going to do anything he could to make this easier for them. Now that he thought the focus-stealing new power from One for All was gone, he could put all his attention on the case at last. He needed to use his frustration and disappointment as a motivator to do better and be more focused, not mope and sulk like a child!
They arrived at the police station and were led to a room — it looked like a repurposed interrogation room. Inside were two tables pushed together which were both covered in stacks of files and papers. Tsukauchi walked in and opened one of the files on the top, and nodded.
"The chief called me last night. He said that he'd grouped all the construction records within the last hundred years that looked even a little bit suspicious in hindsight. Places where a large amount of something could be stored and hidden away, or any simply odd structures. This is it. Apparently, there are hundreds of files here. We better get to work," Tsukauchi explained.
That was how they spent the next few hours. They divided the files up into five smaller chunks and worked through them. Izuku had a trick he wanted to try out, so once they got started reading through all the papers, he took one off the top of his pile and started reading it. One for All roared to life within him, but since Izuku didn't apply the Full Cowling style to it, there were no sparks. The one place that Izuku applied One for All to was his head — more specifically, his brain. Twenty percent of One for All flooded his brain, and everything slowed to about a quarter of the speed it should've moved at. Tsukauchi sneezed, and the sound he made was low and drawn out, and Izuku counted the ten whole seconds it took All Might to say the words, "Bless you." He had sometimes had moments like this, where his perception sped up and he could see things moving in slow-motion like a movie, but he'd thought that was adrenaline and his naturally observant nature. Instead, it seemed like if enough of One for All was focused entirely on Izuku's brain, his thoughts and perception could be enhanced like his muscles. Izuku looked back down and read through the file, and then released One for All and picked up another one.
"Since when did you become a speed reader?" All Might asked. Izuku theorised he'd done two minutes' worth of reading in about thirty seconds, so the scepticism was warranted.
"Just now," Izuku said with a grin. He made a little green spark flicker around his fingertip as he continued to reach for the next file. All Might's eyes lit up in understanding, and he nodded with a proud grin on his face.
Izuku had his unconscious mind working on names for this technique while he searched for strange or unlawful construction jobs. He kept this new move activated the entire time, even if his hand moving at normal speed to grab the next file took half a minute to grab and open it. He figured turning One for All on and off again in such quick succession while it was focused only on his brain was a bad idea. He remembered what breaking his arm had been like back when he had no control over the power. He did not want to fulfil that morbid curiosity. He lost count of how much time was passing, but Izuku estimated that he finished his file pile in about half an hour, which was about two hours for him. He found nothing, which frustrated him, but he'd saved himself a lot of time. Eventually, his head started to hurt, and he had to stop his new technique, which caused a few sparks to flicker around him as he released One for All.
"What was that?" Aizawa asked.
"Sorry. I figured out a new move," Izuku said with a smile. He glanced up at the corners of the room — there were cameras, so he had to be careful. "My Quirk boosts mental power, too, if you do it right, so I used it to read and think faster. I'm done with my pile."
Aizawa looked around, and saw that everyone else was nowhere close to finishing their piles. He frowned, and then clapped. Izuku flinched as a stabbing pain flashed through his head between his temples. Everyone looked at him with varying levels of humour and worry.
"How is your head? It hurts, doesn't it?" Aizawa asked with a little smirk.
"How'd you know?" Izuku's voice broke as he winced again.
"I once knew a hero who could accelerate his perception. It took a massive toll on his brain if he used it too much, or for too long. Your brain is built to handle a certain amount of input at a certain rate. If you start giving it more than it can handle faster than it can keep up, you'll burn out and hurt yourself in a way Recovery Girl may not be able to heal. Be careful with this new technique, got it?"
"Yeah, okay. Got it," Izuku mumbled.
Izuku and All Might split the former hero's pile between them after that. Proving Aizawa right, unfortunately, Izuku's vision began to get splotchy the more he tried to focus, and he could feel a headache beginning right between his eyes. It seemed that when he pushed his brain over the limit with that new technique, the backlash only became evident after he stopped using it. That was going to be fun to juggle with all the other drawbacks of his other techniques and powers.
Izuku figured this was a power he was going to use sparingly anyway, since it was only really relevant when there was a lot of information he needed to parse through quickly, and that didn't happen very often. There was an upside, though — Izuku had thought of a name for this technique: Pinpoint Focus. This new skill used in combination with Danger Sense would make him virtually untouchable, even if the loopholes that had been appearing regarding Danger Sense couldn't be accounted for. If he could accelerate his perception of the world around him to this extent at twenty percent, Izuku felt giddy imagining what he would be capable of at one hundred percent. He'd never get hit by any attack, because his brain could finally move as fast as his body, and that was where he messed up a lot of the time — no matter how many Quirks he unlocked, he had always been held back by having to split his focus four or five different ways while also defending himself and attacking in combat. That was why he tended not to use most of his Quirks in conjunction with each other, and if he did, they were Quirks like Float and Smokescreen, which didn't need a whole lot of conscious guiding, or Danger Sense, which was always active. Now, he could really nail that parallel processing and pull off big moves using two or three of his Quirks at the same time.
By the time that the others were almost finished with their piles, Izuku had begun to take random files from others' piles since his had been done and dusted a while ago, with All Might following his lead shortly after. Izuku leaned over to Aizawa's pile and went to take a file from the top, but got a glimpse of the blueprint he was examining, and paused. It was upside down for him, but he got the gist of it. It was a large obelisk, a tall skyscraper-type building with a single subterranean level. It looked like it was supposed to be built at the lowest point in a valley, which was strange, as Izuku would've thought it'd be at its tallest on a hilltop. The obelisk looked like it had an elevator shaft running up its middle, and then it widened at the top level by a significant amount, and Izuku wondered how it would support itself with that kind of width. He looked back down at the basement level, and wondered why the floor plan was familiar. Suddenly, Aizawa's whole expression changed, and his eyes narrowed.
"This is the Shigaraki house," Aizawa said, locking eyes with Izuku.
"But why's the record here? There was nothing there. Yoichi said they never went back to that house," Izuku said. "Unless … Yoichi never went back to that house. All for One could have gone back after Yoichi had died."
He looked down at the blueprint for the floor plan of the basement and realised that Aizawa was right. It was the Shigaraki house. But that floor plan was the entire home, and it was above ground. Izuku's stomach churned as he got an idea. It wasn't One for All whispering in his ear, Danger Sense giving him weird feedback or a vestige telling him something that wasn't true — Izuku was certain in that moment that he was correct, and that doing what he thought he should would illuminate the way forward for their investigation. He leaned back over and looked at the blueprint for the entire structure, but didn't think of it as upside down, but right side up. It all clicked into place. The basement level wasn't a basement level. The whole thing wasn't meant to be built at the bottom of a valley, it was a hilltop, and the basement level was the Shigaraki house. Looking at it like that made it so much clearer in his mind, as the front-facing view of the basement level was a one-to-one recreation of the view of the Shigaraki house when approaching from the front. That meant that it was entirely possible that the huge structure built off of that house, the obelisk from the blueprint, had been built, but they just couldn't see it — it was underground.
Izuku spun the blueprint around so that Aizawa could see it the way he did. His tired eyes sharpened as he seemingly came to the same realisation that Izuku just had. Their eyes met once again, and it was like telepathy. An entire silent conversation occurred between them in an instant. Aizawa nodded. You're right, good work. Izuku stared at Aizawa, his expression tense and probably more desperate than he would've liked. We need to go. Aizawa shook his head and sighed, his reluctant expression making it clear that he shared Izuku's eagerness to get up and go. Not yet.
"So what does that mean?" All Might asked. He didn't seem to be privy to Izuku and Aizawa's instant understanding.
"It means that Midoriya was right to guide us to the Shigaraki house, but none of us knew why at the time — not even him," Aizawa said, handing All Might the blueprint the way Izuku had shown him to read it.
"According to the writeup, this building was never made, and this blueprint was only a first draft submitted by a Maruta Shiga, which was filed away and never revisited for the forty years the mayor's office has had it. It's noted as strange in the writeup, as construction equipment and materials were moved in to begin construction, but there's no record of this blueprint being realised," All Might paraphrased aloud.
"Forty years?" Izuku asked.
That was significant, but he didn't know how just yet. What happened forty years ago? All Might received One for All from Nana Shimura, who then died, forty- two years ago. Inko Midoriya was born forty-two years ago as well, and All for One ended his cloning program shortly after that. Was this conceived as a new base of operations for All for One after All Might had escaped to America? With One for All out of reach, did he return to the home he'd built in his youth for his brother and prepare to retire? It was a hard idea to fully envision, but it didn't really matter why. There may have been a whole subterranean structure underneath that house that they had to explore. This may have been where the Nomu had come from!
"So, I hope it's obvious to everyone else that this bunker did get built and All for One simply erased the evidence of it," Gran Torino said.
"He didn't erase the evidence of that evidence, though, so we've caught on." Tsukauchi grinned.
"We should get going. Every minute counts," Aizawa said as he stood.
"You're right. Let's get moving," All Might agreed.
Izuku followed the adults outside and wondered if now was the time that he should fly out ahead of them. All Might met his eyes and shook his head, and Izuku accepted that with a tiny frown. They all climbed into Tsukauchi's car once again and took off down the street toward the edge of town. Izuku looked out the window the whole time, getting the strangest feeling that this was too easy. That blueprint had been weirdly obvious. The drive over was too smooth. Maybe it was Izuku being paranoid after Danger Sense had taken root in his brain, but he thought this was the part in the movie where their car got sideswiped by 'accident' because they were getting too close to the answer to the mystery — that, or Katsuki and Kirishima had been given free reign too many times at movie night. Either way, no disaster came to prevent them from driving back up to the Shigaraki home. They all arrived in one piece — or in as many pieces as they'd come to town with, in All Might's case.
The house looked no different knowing that there could have been a massive complex hidden underneath it. Izuku was the one to burst through the door this time, and frowned when, again, nothing inside was different to the time they'd explored the day before. Izuku used Pinpoint Focus for a brief instant, not bothering to suppress the sparks that flew around him as he did. He scanned the room, and nothing was out of the ordinary. He let the technique go and winced as his head throbbed behind his eyes. He walked further into the room to let the other through, and sighed.
From there, the five of them fanned out and searched a room of the house individually. Aizawa took the living room, the room the front door led to. All Might took one of the bedrooms, and came back looking haunted. Izuku took another of the bedrooms, and found a stack of magazines that seemed new. They were all about superheroes, except they weren't about any heroes Izuku knew. Most superhero comic books had become semi-biographical upon the advent of the pro hero. They were about real heroes rather than fictional ones. But these were about those fictional heroes that once had stories told about them, the ones from before heroes, villains, and even Quirks. A man with a lightning bolt motif in red and yellow, a woman with some sort of invisibility power with a number on her chest, and other characters like that. The classics. Izuku had seen in his brief flashes of Yoichi's memories that he loved comic books like these ones when he was young. Did All for One keep them stocked up to somehow convince himself that Yoichi was still alive and reading them, or was it purely sentimental? Izuku didn't have a solid enough grasp on the man's mental state to tell either way.
Tsukauchi and Gran Torino came from their searches and reported finding nothing as well. That was when Aizawa kicked over the couch without a word, just a grunt of effort. All Might looked at Aizawa with a glimmer of pity in his eye, but that quickly transformed into a look that told Izuku that his mentor had just realised something. He was about to ask what that thing was, but All Might looked right at Izuku and grinned.
"Could your Air Force destroy everything in this room?" All Might asked.
"Probably, but why—"
"That's a good idea. Alright, everybody, let Midoriya do his thing," Aizawa said.
The adults left the room, barricading themselves behind the doors that led to the bedrooms. Izuku wanted to call out and ask for an explanation, but he figured things like this tended to explain themselves once they were over. Izuku powered up to twenty percent Full Cowling style, and stood as close to the exact centre of the room as he could estimate. He aimed his hands down at the floor, one gripping the other to keep it steady, and pressed his middle finger against his thumb. A flash of lightning and a rush of wind accompanied the flick of his finger, and soon the whole room was ruined. The wind blast he sent forward hit the floor and then spread outward, bouncing back and forth and ripping the furniture to bits through sheer wind pressure alone. The couch, the shelves up against the wall, the table in the corner, everything that could be taken apart was shredded by Izuku's Air Force. The only reason he remained standing was that he'd reinforced his body with One for All. The blast had tugged on his legs, but he'd stayed steady. A current of air came at him from behind and pulled his cowl up onto his face by chance.
When the violent winds died down, the adults returned to the room. They looked around, All Might and Gran Torino and Tsukauchi shocked and alarmed. Izuku knew what they were thinking — this was technically a crime, destruction of property. Aizawa came out of his hiding place, opening the door only to have to climb over it when it fell off its hinges in the doorway. He stepped over all the debris and scanned the room, pausing when he looked at the wall where the shelves had once been. Izuku followed his line of sight to discover that there was a segment of the wall, a square about the size of a person's hand. Aizawa walked over to it and pressed his hand to it, eventually realising he could slide it to the left. Doing so revealed a keypad behind the false bit of wall. Aizawa crouched down and went to try a passcode, but the blue screen of the keypad flashed green for a moment and a voice rang out from nowhere.
"DNA key — accepted," the robotic stranger declared. "All for One."
Izuku's heart stopped beating in his chest. Either that, or All Might's did, by the look on his face. They looked at each other in horror and realisation. The little gears in Izuku's brain churned as they raced toward a conclusion, and ground to a halt when they found one. All for One was his father, so that should be the simple answer, right? Wrong — Inko Midoriya was also technically a more or less precise genetic recreation of All for One, so she had all his DNA, too. That meant that one-hundred percent of Izuku's DNA had come from a single donor, and that donor was All for One. He would read on devices that scanned DNA as a copy of him, down to the genetic level, because he was. Fortunately for them, that had worked in their favour this time, because the thing that kept others out was the thing that would let them — more specifically Izuku — in. They didn't even have to put in a code for entry, because All for One was home.
Aizawa scoffed. "Of course."
"What's this about?" Gran Torino grumbled.
"Long story," All Might said with a grave tone of voice.
"Do you … care to tell it?" Tsukauchi asked with a wide-eyed stare.
"Not really," Izuku said, much the same way All Might had.
Tsukauchi and Gran Torino seemed to get the gist of it simply from reading their expressions, and Izuku was glad they didn't ask for details, but it didn't help the fact that his parentage had been brought up in the first place. Izuku would prefer it if as little people knew as was possible, but more and more, it felt like a truth he had to face if he wanted to confront this new threat. Izuku did not have much time to ponder this, though, as in the moments after the device recognised Izuku's genetic code, the floor shook. It rattled, sending the different pieces of debris from Izuku's little rampage clattering across the floor. The entire bottom of the room suddenly sank, forcing everyone to stumble and regain their balance. Izuku looked around as the floor lowered itself into a dark shaft, and realised that the entire floor was the base for the elevator shaft he'd seen in the blueprint.
"Good thinking, Eraser," Tsukauchi said.
"It was obvious," Aizawa said plainly. "Be on guard. We have no idea what'll be waiting for us at the bottom."
Izuku brought up Full Cowling again and powered up. The flickering aura around him illuminated the elevator shaft, allowing Izuku to see his allies. The elevator took around a minute or so to reach the bottom — or whichever floor its destination was. For all they knew, the underground complex could have many more floors deeper than the one it took them to. After all, the blueprint was forty years old. They could've made additions. There wasn't a whole lot they could do, though, so they went where the elevator took them.
The area it took them to was dark, but the flashing electrical discharge around Izuku's body, as well as the miniature flashlights that Aizawa passed around — did he just have those on him? — allowed them to see just fine. Exploring, Izuku found an entire wall of computer screens that were turned off, though there was no dust on the screen nor on the complicated-looking keyboard he found at the desk beneath the screen, so he guessed it had been used recently. Along the wall opposite the computer, a string of empty tanks decorated the wall. They were identical to the tanks he'd hidden behind to escape All for One for a while in Kamino, the ones he'd stored the inactive Nomu in. That had been the time he'd manifested Smokescreen, which he grew more thankful for every day. As well, there were five machines that were different from the typical preservation devices for the Nomu. They looked like tanning beds, except the metal of it radiated cold. They were smaller, clearly for approximately human sized occupants. All of this machinery sent a chill up Izuku's spine, and he suddenly remembered his gut instinct that it was too easy. They'd found the thing they'd been looking for — why had nothing tried to stop them?
"This is it, the storage facility for the Nomu," Tsukauchi said, clearly amazed. He turned and approached the computer wall. "Let's see if this works."
While Tsukauchi turned on the computer and tried to navigate its files, Izuku continued to explore. He jogged up to Aizawa when he made a grunt of surprise, and realised that it was because there were splatters of blood in seemingly random spots. It was dried, and it didn't smell, which was a shock for Izuku, but didn't look all too surprising to Aizawa. Izuku moved on from that while Aizawa went and got a blood collection kit from Tsukauchi, and came across a desk tucked away in the corner of the room. Izuku pulled on the drawers with his normal strength, but they were locked, so he yanked harder with about three percent of One for All, and they opened easily. Inside were a collection of files, which Izuku sat down to read. All the files were labelled Children for some reason, which did not inspire confidence in Izuku that these would be a fun read.
The first file was about Subject 1. It appeared to be a woman, judging by the photograph attached. She seemed to be in her early twenties, and was pretty in a way that one would see on the street every so often but not really comment on. Izuku always felt a little bit bad when people called him plain-looking, but she had much of the same qualities as he did in that regard. Listed was her Quirk, named Psychic Leech. It did not tell Izuku what the Quirk did, but he got the impression that she could steal energy from peoples' thoughts, or something similar. Maybe taking memories was part of it, too. Subject 2 was a young-looking boy, about twelve or thirteen, with prominent freckles and wild messy hair, like Izuku's. His Quirk was noted as Blink, but yet again, there were no details. Perhaps he had the power to teleport short distances or to places he could see, and it was triggered by blinking. Subject 3 was a behemoth of a man, as large easily as the Nomu but still visibly human, whose Quirk was named Powerhouse. It was possible he was a power type, strong and tough. Izuku's eyes were drawn to Subject 3's nose, as it was the exact same shape as his own. Subject 4 was a girl that could've been Izuku's age or a little bit older, and the shape of her jawline had him looking in a mirror. Her Quirk was listed as Shape, which could've meant anything from reshaping objects or shapeshifting. The final file was about Subject 5, who was a perfect recreation of a young All for One, like the version of him Izuku had sometimes seen in his visions of the past users' memories — and, now that Izuku thought about it, Subject 5 looked like Izuku thought he might as an adult. Telekinesis was Subject 5's supposed Quirk, and it didn't take a whole lot to figure out what that could mean.
Izuku sat there and stared at the files for a long time. He was fixated on these subjects' appearances. They all shared at least one common physical trait with Izuku. Subject 1's plainness, Subject 2's freckles and hair, Subject 3's nose shape, Subject 4's jawline shape, and Subject 5's uncanny resemblance to both All for One and Izuku. He was disturbed by the similarities to himself he saw in these people, and didn't want the idea that was brewing in his head to be true. The files were all titled with Children. These couldn't be other attempts that All for One had made at having kids who could steal Quirks from a distance, could they? Were they naturally born people or did he make them, like he'd made Izuku's mother? The special pods, which lined up number-wise with the files, seemed to support the theory that they were clones, but that meant that All for One had lied about discontinuing his cloning experiments after Inko Midoriya had been deemed a failure. Izuku of course had expected some of All for One's unhinged monologue back at Kamino to be exaggerations and lies to get his son on his side, so why had Izuku taken his word for it about the clones? He was such an idiot!
He regrouped with the others, files in hand, to tell them about what he'd discovered. Izuku went to speak, but metallic grinding suddenly rang out around the laboratory. Izuku flinched, but Danger Sense didn't go off, so there was no immediate danger. He looked around and noticed the real threat. The elevator was going back up, quickly sealing up their exit route. If it closed completely, they'd be trapped inside.