On the western continent of the United States stood a city known as Snowfield.
At this season, Snowfield was hardly a tourist destination. From the perspective of its surrounding geography, the city itself was an anomaly, an unnatural outcropping with no sense of beauty.
It had no connection to farmland. To the north stretched a canyon vast enough to rival the Grand Canyon. To the west lay dense, unbroken forest. To the east spread a wide lake basin. And to the south, an expansive desert.
Yet for reasons unknown, the number of people flocking to the city had steadily grown these past few months. The chatter of magi pouring into Snowfield was drowned beneath the blaring of loudspeakers.
In the city's northwest sector stood a privately run prison, common enough in America. Its name: Kozman Special Correctional Center.
Beneath that prison, in a basement facility, every manner of surveillance footage—whether public or secret—streamed live across countless monitors.
Beyond that, bird-shaped familiars patrolled the skies, relaying visual data.
The master of this surveillance system and the familiars was Fadius—one of the masterminds behind the American Holy Grail War.
A magus affiliated with a U.S. government institution, once a student of the Clock Tower. His family had transformed Snowfield's leyline network, and with "someone's" help had stolen fragments of the Fuyuki Grail. With them, they summoned false Servants to supplement the city's spiritual foundation, paving the way for a True Holy Grail War.
"...What are you doing here?"
Fadius's voice was calm, but beneath it lurked clear irritation.
"Ehh? Your reaction feels so cold. Can't I drop by just because I feel like it?"
From the shadows, a girl peeked out.
She looked no older than fifteen, dressed in gothic lolita fashion in black and white, a parasol in hand.
Her name—Francesca.
"It isn't time for us to be in contact again."
"Oh~ is that so? And here I didn't realize. Want me to kneel right now and beg forgiveness? That could work too. Having a cute girl kneel in public and swear fealty—don't you think that has a real conqueror's charm?"
She twirled her parasol and giggled impishly.
"Say what you came to say. There's no need for extra words."
Fadius regarded Francesca with extreme caution. She might appear youthful, but she was in truth a magus who had lived for who knows how many years—an entity that demanded constant vigilance.
Back in the Third Holy Grail War at Fuyuki, the Master of Assassin had been a puppet-maker with ties to Fadius's family. He had left the memories of that war sealed within one of his dolls.
Later, Fadius's grandfather had allied with American politicians and the military, seizing Snowfield from the indigenous people. Its leylines were of a quality rivaling Fuyuki's. They reshaped those leylines on a massive scale, drawing them closer in form to the Eastern city.
By the time the torch passed to Fadius's father, Francesca—working through her ties to the government's shadow operations—helped steal a portion of the Fuyuki Grail.
"How amazing, how amazing! Even when I tease you like this, your expression doesn't change. You really are an iron-faced machine. It makes me admire you a little, you know!"
The violet-haired girl laughed at his cold, unmoving face.
"You flatter me, Miss Francesca."
"Ugh, what a boring reply."
Disappointed at his lack of reaction, the girl waved her hand lightly and continued:
"In the world of magecraft, they say there's a great labyrinth—created to conceal both itself and a supreme treasure. A labyrinth vast enough to warp dimensions. Yes… the Grand Labyrinth, Alcatraz."
"...What?"
Fadius knew of it. According to his knowledge, it was the domain of one of the Dead Apostle Ancestors with deep ties to the Church. A place impossible to enter, impossible to leave—a twisted and cursed realm.
But why would this old monster suddenly bring it up?
In the next instant, the air around Francesca's smile shifted.
"A supreme treasure. Whether it's a record that inscribes all of the world, an artifact proving the love of the Lord of the Church, or even a replica of the cosmos itself—put simply, something absurdly powerful."
Her smile remained innocent, but her eyes gleamed with the cruel fire of vengeance, the look of someone dreaming of tormenting the world.
"And yes, such a treasure—I want it very, very badly. Of course, there's the argument it ought to be made available to humanity at large. But a labyrinth that can't be opened? At the very least, it should become a place one can challenge. If a ritual forged by the world itself unlocked it, just imagine. Whether humanity blossoms across the cosmos or stumbles into ruin—it would be humanity's own hand that determines it."
Her sweet voice whispered to the expressionless Fadius, but it was as if she were murmuring words of love to the world itself.
"In that way, the labyrinth's lock will be undone… and then, we can ravage everything to our heart's content!"
When her words fell, her expression turned cold again. In a calm, flat voice, she added:
"That would be… utterly sublime."
---
Snowfield, eastern district, lakeside villa
"They're here again…"
The summoned Assassin sensed the ominous presences gathering outside the gate.
Around her lay the corpses of magi. As a Hassan, she could not condone such heretical rituals—so she had slain the ones who had summoned her.
"You are… a Servant in this Holy Grail War?"
Ordinarily, Assassin should have ignored the intruders and killed them without hesitation. After all, they were Dead Apostles.
Her faith in the Hassan creed was absolute. To her, magi and worshippers of foreign gods were enemies to be erased without mercy. The existence of Dead Apostles was blasphemy itself.
And yet, through the knowledge the Grail had bestowed, she immediately understood her fate.
Her one wish was to personally consign such heretical beings to the void.
She also knew that throughout history, several of her sect's leaders had sought the Grail as well.
That knowledge brought her only sorrow. She bore no hatred for those leaders, nor contempt.
The only thing worthy of hatred was the thing that deceived them—the "Holy Grail War" itself, and its participants.
But the black-haired girl before her, though a Dead Apostle, radiated… that.
Her memories, her soul, her body tempered by a lifetime of faith—she recognized what it was instantly.
Tears welled in Assassin's eyes.
This was something acknowledged by the Great Predecessor himself—a sanctum she had never reached in life.
Though a Dead Apostle, the girl shone with dazzling radiance.
"I—"
As Assassin began to speak, the girl—Arcueid's sister, Altrouge—waved a hand to silence her. Her gaze fell on a magus's corpse at Assassin's feet. She said quietly:
"Jesta… no, when you were human, your name was Dorothea, wasn't it? A magus of great power, cast out of the Association, taken in by Van-Fem and made a Dead Apostle. And yet, how utterly hideous you've become."
"Y-you are… Princess… my lady, I—"
At that moment, Assassin realized the magus's corpse was stirring. He had only been feigning death. But with nothing more than a glance from the Princess, his body dissolved into smoke and ash.
As sovereign of blood and contracts, acknowledged leader of the Dead Apostles, Altrouge required no effort. Though grievously wounded and long absent from the world, with but a thought she could annihilate any lesser Apostle.
"There. Your contract with that one is gone. Do as you please now."
Indeed, Assassin felt it—no more prana flowed into her. Her Dead Apostle Master was well and truly dead.
In truth, Altrouge had little interest in interfering. The Grail did not concern her.
Her reason for coming to Snowfield was simply to see if she might encounter the one Brad had spoken of—someone who looked exactly like Arcueid. But Jesta had grown insufferably arrogant, his obsession with using the Grail to destroy the world grating on her. So she had dealt with him in passing.
"Please… wait."
"Oh? Do you have something to say to me?"
Just as the Black Princess turned to leave, Assassin called out to her.
"My lady… I beg you… show me the path home."