"Ugh... what even happened here?" Scanning the completely devastated street, Shirai Kuroko felt her head throb in pain. Her eyes filled with despair. "Ahh, my vacation is gone... my precious time with Onee-sama is gone..."
"Ahhh! Isn't Academy City supposed to be the safest city in the world?! Why are there so many violent attacks lately?!" Kuroko tugged furiously at her twin-tails, nearly on the verge of a breakdown. It would've been fine if these incidents happened in another district, but why did it always have to be School District 7—her jurisdiction?
Ignoring the frantic Kuroko beside her, Misaka Mikoto stood silently, her face serious as her eyes swept across the rubble-strewn ruins. Her heart trembled slightly. From the traces left at the scene, it was clear—none of the destruction was caused by energy-based attacks.
Instead, everything pointed to purely physical damage. Apart from the clean cuts likely caused by bladed weapons, most of the devastation consisted of massive spiderweb-shaped cracks and craters.
"It must've been caused by two people... and judging from the pattern, they were fighting each other. But with this level of power—who could it be?" Mikoto murmured. She had some guesses, but no certainty. There were indeed a few espers with exceptional physical capabilities among the Level 5s... but could it have been him?
Soon after, Anti-Skill officers arrived on the scene, cordoning off the entire area. Even they were growing weary—two major incidents in one night, both involving catastrophic property damage. It was more than enough to drive anyone mad.
...
jonaGardeN Family Restaurant.
Thanks to Selene's intervention, Mikoto hadn't unleashed her Railgun. Though her first two test shots had caused minor damage to the city's power grid, the overall effect was minimal. Unlike in the original timeline, power was restored within a single day.
At the same restaurant as before—but this time, they had reserved a private room. Selene had no other choice; after all, five people dining together made for a rather odd sight.
A relaxed-looking Selene sat at the head of the table, surrounded by a tense Kamijou Touma, a pensive Kanzaki Kaori, an impatient Stiyl Magnus, and a sulking white-robed nun, Index. The atmosphere was thick enough to choke on. Once Selene finished ordering, the waiter practically fled the room.
Kanzaki's gaze shifted toward Selene, her heart conflicted. So she really wasn't even using her full power against me...
In the end, it was Kamijou who broke the silence. He simply couldn't help it—his credit card was fried, his apartment destroyed, and, to top it all off, he was completely broke. "Uh... why are we in a restaurant? I... don't have any money right now!"
"Alright, alright, I'll cover it for you—huh? Why are you all looking at me like that? Oh, fine, fine. You're all broke too since you're not from around here, right? I'll pay for everyone," Selene sighed helplessly as the others turned their eyes toward her. She couldn't refuse that collective stare.
"Alright then... now that we're all settled, let's get to the point," Selene began, leaning forward. "You claim you don't want what's in Index's head, and that you're her friends. Then why were you chasing her and hurting her?"
Index blinked in confusion, her eyes flickering with uncertainty. But when she glanced at Stiyl and Kanzaki sitting nearby, she instinctively tried to shrink away.
"To protect her," Kanzaki said at last, her voice strained but resolute. "When she fled, she drew too much attention. We acted to ensure she wouldn't be captured by those who might exploit her."
"Lies! You were trying to kill me!" Index shouted, disbelief written all over her face.
Her words cut deep. Both magicians flinched visibly, their expressions pained.
"Then why use such a brutal method to 'protect' her?" Kamijou demanded, his voice rising.
"Because..." Kanzaki hesitated, then continued in a low voice. "Over 85% of her brain capacity is occupied by the 103,000 grimoires stored within her mind. She can only rely on the remaining 15% to maintain her basic cognitive functions." She closed her eyes tightly. "Her usable brain capacity is only 15% of a normal human's... yet she possesses Perfect Memory. If she continues to live like an ordinary person—constantly remembering new information—her brain will eventually overload."
"If we don't erase those memories periodically... she'll die."
"So, as her friends, you've been erasing her memories every year—even if it means she forgets you or grows to hate you—because you believed it was the only way to keep her alive. Fine. I won't judge that."
Selene didn't condemn them. Their intentions were good, and from their limited perspective, it was the best solution available. And since she wasn't particularly close to Index, she saw no reason to act self-righteous or lecture them from some moral high ground—because she knew someone else would.
"Do you really want her to live in a false paradise forever?" Kamijou Touma suddenly stood up, his voice filled with righteous anger. "A life without memory—that's not heaven! It's hell! You're only protecting your own feelings!"
As expected, the ever-idealistic Kamijou Touma had taken the stage, overflowing with conviction—and conveniently, he happened to have the power to change things.
"Shut up!" Stiyl snapped, trembling with emotion, his shoulders shaking. "What do you know?! Do you think it's easy to watch her lose her memories again and again?! You think we wanted this?! We tried everything, and nothing worked!"
"'Tried everything'? Using your magic-side methods again, I assume?" Selene interjected, her tone calm but cutting. "Haven't you ever read a science book?"
"Eh?" Kanzaki blinked, caught off guard by the strange question. "No, we haven't... Is there some kind of connection?"
Selene sighed deeply. "In March 2014, Nature published a study. It analyzed the neural structure of just thirteen mouse neurons—and the data used totaled one terabyte. Now, a human brain weighs about 1.4 kilograms and contains roughly one hundred billion neurons."
"Huh?" Kanzaki looked puzzled. "What does that mean?"
"It means that, in terms of storage capacity, a single human brain can theoretically hold information equivalent to ten thousand libraries—each containing ten million books."
Kanzaki and Stiyl's eyes widened in disbelief. If what Selene said was true, then everything they'd been told was a lie. "Wait—you're saying... Index's brain could never reach memory saturation?"
Selene smiled faintly. "Exactly. Let me put it another way—how far back can you remember?"
"About ten years," Kanzaki replied automatically.
"Then that means you can remember ten years' worth of memories without issue. So if Index is said to function at fifteen percent capacity, that means your memory works at ten times her supposed limit—about 150% of a normal person's capacity. Yet your brain hasn't overloaded, has it?"
Both magicians froze, chills running down their spines. If Selene was right... then what had they been doing all these years?
"The human brain doesn't overload from a bit of extra information," Selene continued. "A normal brain can store memories spanning roughly 140 years. Memory also isn't linear—it's categorized and prioritized. The brain naturally forgets what it doesn't need. Even if you crammed in endless knowledge, it wouldn't crush the rest of your memories."
She paused, folding her hands before her lips thoughtfully. "And more importantly... there's something foreign lodged in her throat."
"What?!" ×4
The other four stared blankly at her.
"You know more about magic than I do," Selene said calmly. "Take her to the restroom and check for yourselves. See it with your own eyes, then decide what's true."
There were no objections. Even Index, sensing the gravity of the situation, stayed quiet as Kanzaki led her away.
Minutes later, they returned—both looking grim. "It's true," Kanzaki said darkly. "There's a magical object embedded there... from the Church."
Stiyl crushed his cigarette between his fingers, his expression hardening. The realization hit him like a hammer. They had been deceived. He had hurt her—over and over again—for nothing.
"...How could this be..." Kanzaki's voice trembled, her eyes glistening with tears of guilt and sorrow. "Then everything we did to her... all of it was meaningless..."
"Who told you her brain was at fifteen percent capacity—that memory overload would kill her?" Selene asked coldly.
"The Archbishop of the Anglican Church," Kanzaki whispered.
Selene gave a dry laugh. "Then there's your answer. Everything that's happened—all her suffering—was caused by the Church itself." Her gaze shifted toward Index. "You were never the problem."
Then, turning back to Kanzaki and Stiyl, Selene continued, "Even if—for argument's sake—the fifteen-percent theory were true, doesn't the magic side have countless spells dealing with memory control? Why not teach her one, let her manage it herself? Unless..." Her tone darkened. "Unless that thing in her throat is a magical failsafe created by the Church—to control the living library known as Index. And the annual 'memory wipe' is just the trigger that keeps the control mechanism active."
"No... That's impossible... Why didn't the higher-ups tell us anything like this?" Stiyl muttered, his pupils dilating. The sense of betrayal was suffocating.
Selene shrugged. "That depends on what your Church's leaders are scheming. In Academy City, even our elementary students can access basic neuroscience texts. Go read one. I've said all I needed to. What you do next... is up to you."
With that, Selene leaned back, ignoring them entirely as the food finally arrived. She'd said her piece—and now it was time to eat.
...
By the end of the meal, only Selene and Index were eating with any enthusiasm. The rest sat in heavy silence, each consumed by their own thoughts.
After settling the bill and exchanging contact numbers, Selene teleported away without ceremony. She'd had her fill of fighting and lecturing for one day—now, all she wanted was a long, hot bath.
Once she was gone, Kanzaki and Stiyl exchanged a wordless glance before quietly leaving as well. There was too much to investigate—too much to uncover.
A few minutes later, only Kamijou and Index remained. The boy sighed helplessly when he saw her clutching his sleeve, stars in her eyes. "I don't even have a home anymore," he groaned, rubbing his head in defeat. "Guess I'll have to crash at Komoe-sensei's place for a while..."