Japan, Academy City.
In an utterly ordinary single-bedroom apartment, a high school boy with messy, spiky hair and slightly tanned skin was standing on the balcony, gazing into the distance.
This boy's name was Kamijou Touma, and in this city full of espers and geniuses, he was one of the most unremarkable majority.
If there was anything special about him, aside from his right arm, it would probably just be that he was a bit more unlucky than most people.
Letting out a deep sigh, Kamijou Touma turned around and looked at the girl lying on his bed, dressed in a white-and-gold nun's habit, with a rather complicated expression on his face.
Just a few days ago, he had found this girl—named Index—hanging onto the railing of his balcony.
Driven by a sense of "help when you can," he had taken her in for the time being and even squeezed extra food expenses out of his already tight allowance.
However, his misfortunes did not end there.
Because Index seemed to be pursued by some organization, Kamijou Touma, who had taken her in, also got dragged into even more troublesome situations.
"Such misfortune!"
Kamijou Touma couldn't help but wail inwardly in despair.
Still, since things were already this unlucky, surely nothing more troublesome would come knocking, right?
The unlucky boy could only comfort himself with such naive hope.
Unfortunately, he was wrong.
"VMMM—!"
A spatial distortion sounded out as a deep blue, twisted portal appeared right before him.
That profound darkness resembled a wormhole in the universe, devouring every speck of light and making it impossible to see what lay beyond.
However, Kamijou Touma was not a stranger to bizarre occurrences. Though he didn't know what this was, his instincts screamed that it was bad news. If he didn't want to get wrapped up in more trouble, he should run immediately.
But just as he was about to grab Index, who was lying on the bed eating snacks, and dash out the door—
A slender arm reached out from the portal and grabbed his.
Soon after, a girl about the same height as Index, dressed like a witch, appeared inside his room.
"No time to explain, get in the car!"
Kamijou Touma felt a tremendous force pulling on him, rendering him completely unable to struggle.
Given her sudden appearance through a bizarre portal and such immense strength, Kamijou quickly deduced that this girl wasn't normal.
Could it be... she was with those people who were after Index?
But if that were the case, why come for him and not Index?
A flood of questions surged through Kamijou's mind, but the witch-like girl had no intention of explaining anything.
With a powerful tug, he was lifted into the air and thrown toward the portal.
However, just as Kamijou Touma thought he was about to be flung into some lightless prison, he instinctively raised his right hand—and the deep, dark portal abruptly vanished.
"Ahhhhh—!"
With the portal gone, Kamijou was hurled by inertia into the balcony railing, crying out in pain.
Any other high schooler might've been rolling on the floor in agony by now.
But having been plagued by misfortune all his life, his body had become tough. After a single shout of pain, Kamijou quickly forced himself back onto his feet.
"Who are you?! What the hell do you want?!" he cried out in panic.
Yet the witch-dressed girl still showed no desire to communicate.
Seeing that he hadn't been thrown through the portal, her expression darkened as she strode toward the injured Kamijou.
In her hand, a wand shaped like a key gradually formed.
When Kamijou saw her raise the wand and point its sharp tip at him, he thought he was about to be killed and reflexively raised his right hand to block.
"Sealbreaker: Close!"
It sounded like some kind of incantation.
But Kamijou felt no effect from it.
Instead, the moment the wand touched his right hand, it vanished entirely.
The witch girl was stunned, then summoned the wand again and tried several more times.
But each time, the result was the same—the wand vanished upon contact with his right hand.
"...My apologies."
The witch girl finally sighed as if giving up.
With a flick of her wand, the same deep blue portal reappeared beside her.
Without hesitation, she turned and stepped through it.
Watching the portal close before his eyes, Kamijou Touma remained in complete disarray.
"What the hell just happened?!"
Meanwhile, at the base—
The portal opened, and Kaguno Natsumi stepped back into view.
The creators and creations present all turned expectantly toward her, but the boy who should have been with her was nowhere to be seen.
"It failed," Natsumi said helplessly. "He simply can't pass through the spatial portal. The Sealbreaker just isn't strong enough to suppress Imagine Breaker."
"As expected..."
"What a shame. Kamijou Touma really was the ideal candidate."
"But there's nothing we can do about it."
Seeing the failure of the plan, the others were only mildly disappointed rather than devastated.
After getting a good rest, Company Director Tachibana had shared his plan based on Kamijou Touma's abilities.
During the ensuing discussion, a clear issue had surfaced.
The strategy itself was sound.
The problem lay with Kamijou Touma himself.
His ability, Imagine Breaker, is passively activated.
In other words, unless his right arm was amputated, there was no way for Kamijou Touma to pass through a portal created by supernatural power.
Still holding onto a sliver of hope, Kaguno Natsumi had gone to the world of A Certain Magical Index to see if the Sealbreaker could suppress his ability.
But unfortunately, it had failed.
After confirming she couldn't bring Kamijou back, she had no choice but to withdraw.
Taking him away wouldn't have been hard—he appeared to be just a regular person. That's also why he made it onto the list of fifty candidates.
Even if Aleister Crowley had the entire city wired with surveillance and could detect anything happening in Academy City, it was impossible to respond instantly to everything that happened.
So Kaguno Natsumi approach was all about a lightning strike—appear before you notice, and be gone before you can react.
"Since Kamijou Touma is a no-go, we'll have to go with the backup plan," Director Tachibana said, pointing to another name on the list.
"Alright, Natsumi—Osamu Dazai is your next target."