"Holy crap!"
Accompanied by a cry from Hisazakuro Nagasawa that was anything but ladylike, Hasegumo and Nagasawa stood before the mountain of his hometown. For a long time, neither could speak, their eyes filled with nothing but pure astonishment.
How did the story develop this way? Let us take it slow.
As established previously, Hasegumo was bringing Nagasawa back to his hometown to get married. Now, the curious reader might ask: where exactly is Hasegumo's hometown?
First, a bit of geography. Sendai, located in the northeastern part of Honshu in Miyagi Prefecture, is the largest city in the Tohoku region. It's known as the "City of Trees" and the "City of Food" due to its rich natural environment and cultural heritage. It is also the hometown of Yuji Itadori.
Neighboring Sendai is Yamagata Prefecture. Connecting the two is a mountain range known as the Ou Mountains—and that is where Hasegumo grew up.
Now, back to the matter at hand.
Following the Hokkaido Incident, Hasegumo prepared to take Nagasawa home. They had discussed the "marriage" and, since neither liked making a scene, they decided the plan was simple: visit his grandfather's grave to pay their respects, go register for a marriage certificate, and call it a day.
That was the plan. However, Hasegumo hadn't actually been back in over ten years. The two stayed in a hotel for a night to rest, arrived in Sendai by train the next morning, and then began trekking toward the mountains along the highway.
They walked and chatted, enjoying the scenery.
It wasn't until they were about two hundred meters from his old home that Hasegumo's brow began to furrow. He hadn't noticed it from a distance, but as the peak finally came into clear view, the reality of the situation hit him.
A massive Curtain had split the mountain range in two. On the left—where Hasegumo's home used to be—everything was covered by the black barrier. On the right, where Tamamo-no-Mae had once been sealed, the trees were lush and green, appearing perfectly normal.
Neither of them were rookies. Upon seeing the Curtain, Hasegumo stepped forward and reached out a hand; Nagasawa followed suit. Both passed through without resistance. Clearly, the barrier's rules weren't designed to keep people out.
They checked their phones—surprisingly, the signal was fine. Deciding to see what was going on, they strode deep into the Curtain.
...
What used to be a towering cliff now looked as if a Gundam had sliced it clean down the middle with a giant anti-ship sword, leaving only a perfectly flat half-mountain. If it had just been that, they wouldn't have lost their composure so thoroughly.
On that remaining half-peak, a high perimeter wall circled the area. Streams that once flowed down the mountain now trickled into the enclosure through small openings at the base of the wall. Inside, the space was filled with buildings of all sizes, centered around a stunning ornamental lake.
Hasegumo, being a man of some culture, couldn't help but have a certain classical rhapsody come to mind:
"Two rivers flow gently into the palace walls. Five steps a floor, ten steps a pavilion; corridors wind like silken belts, eaves peck high like birds of prey. Each building follows the terrain, their structures interlocking and soaring...
Coiling and circling, like beehives or whirlpools, rising in thousands of clusters...
A long bridge lies across the waves—is it a dragon appearing without clouds? A covered walkway spans the sky—is it a rainbow without rain? High and low, a misty maze... Warm songs from the stages bring the breath of spring; cold sleeves in the dance halls evoke a chilling storm. Within a single day, within a single palace, the climates do not match."
Well, there were no concubines or court ladies, so it wasn't quite the Afang Palace. But even so, this sprawling Nordic-style architecture across a mountain peak was breathtaking.
Despite the abundance of buildings, Hasegumo scanned the area and sensed no living people. He squeezed Nagasawa's hand, wondering which sorcerer had decided to start a massive civil engineering project in his backyard.
Next to him, the "less-than-cultured" Nagasawa could only manage another, "Holy crap."
The two remained silent for a moment, lost in their own thoughts.
Hasegumo was wondering if this construction-obsessed bastard had bulldozed his grandfather's grave.
Nagasawa, meanwhile, stole a glance at Hasegumo. This guy is actually this rich? He'd said he lived in the mountains as a kid, and she'd pictured him struggling through a life of hardship. Instead, he lived in a palace so luxurious even the Emperor would be jealous. It was... incredibly enviable.
"Eh?" Hasegumo felt a chill and realized Nagasawa was looking at him with a very strange expression. He quickly explained, "It wasn't like this ten years ago! Back then..." He gestured vaguely with his hands. "The mountain was whole, and there weren't any houses!"
"You evil, feudal landlord! Taste the iron fist of capitalism!"
...
The two joked and bickered as they hiked up the mountain. They pushed open the unlocked gates, marveling once again at the sheer scale of the architecture.
As they walked along a small path paved with granite tiles, Hasegumo's ears twitched. He caught a faint, rhythmic sound—the metallic clink-clink of a hammer hitting stone.
"This way." Nagasawa hadn't heard it, but she was surprised Hasegumo seemed to know where he was going. After following him for a while, two figures working atop a two-story spire came into view.
One figure had blonde hair fluttering in the breeze. He wore a red sleeveless T-shirt and denim cargo pants. He held a sledgehammer in his right hand and a rivet in his left, hammering away at the eaves. Clearly, this was the source of the noise Hasegumo had heard.
Below the house, a man with a black bowl-cut was energetically mixing cement.
Hasegumo squinted. Wait, isn't that Yu Haibara? He stepped forward to call out, and after a round of explanations, Hasegumo and Nagasawa finally understood the situation.
It all started ten years ago. Back then, Suguru Geto's ideology was beginning to drift toward the dark side. The group from Jujutsu High had tricked him into coming to these mountains for a "vacation," hoping he'd relax. Through a series of twists and turns, not only did Geto's mindset mature, but he also gained the Special Grade curse Tamamo-no-Mae and mastered his Maximum Technique: Uzumaki.
But none of that was as important as the ancient Barrier Technique manual he'd acquired. According to the records, by using a specially configured Curtain combined with a controllable Special Grade curse, one could create a "Perfect Barrier" that automatically absorbed Cursed Energy and prevented new curses from being born.
When he left this "treasure trove" that had granted him so much, Geto decided to run an experiment. The original inhabitants of this "Peach Blossom Spring" had already moved away; according to Hasegumo, he had lived there for years without seeing another soul. So, Geto left the Special Grade curse Novski behind.
On the surface, he left the curse to finish some minor repairs on the existing houses. In reality, right after the group graduated and before Hasegumo started his martial arts training, Geto made a move.
While packing to leave Japan for America to assist Yuki Tsukumo, Geto took a detour to Sendai. Although Novski possessed immense Cursed Energy, it had zero desire for combat. Geto set up the Curtain and designated Novski as the resident Special Grade of the barrier—a practical test to see if the technology was stable.
Ten years passed in the blink of an eye. Geto hadn't forgotten about it, but the distance was an issue. Every New Year, when he returned to Jujutsu High to visit everyone, he would simply check from the Shinkansen using Cursed Spirit Manipulation to confirm the Curtain was still active. He never actually went inside to check.
Left to its own devices, the Special Grade Novski demonstrated the terrifying potential of its rank. It began a massive "environmental renovation." With the help of only one other person, it spent ten years building this palace... and calling it a palace was no exaggeration. However, the architecture was primarily in the Russian style—reminiscent of the Kremlin—as a tribute to the "Red Nation" where it was born.
As for Yu Haibara, ever since he'd helped with the labor once, he couldn't get it out of his head. Although his day job was still exorcising curses and practicing martial arts, he'd stumbled upon the Curtain during a random mission. He wandered in, saw Novski literally moving mountains, and found himself joining in. Novski was more than happy for the help.
Thus, whenever Haibara had free time, he'd run over to assist. The construction progressed slowly but surely.
As the saying goes: A tower of ten thousand feet rises from the ground; a thousand-year forest can vanish in a day.
It was only today that this magnificent structure was discovered by someone other than its builders.
"You guys... building all these houses... did you get government approval?" Ever the mood-killer, Hasegumo's first sentence was incredibly unromantic.
However, Yu Haibara was prepared. He tossed his trowel aside, pulled out his phone, and began explaining the law to Hasegumo. "Kumo-senpai, look here! Private-use buildings don't require an application. As long as they aren't for commercial sale, you can build whatever you want."
"I thought one household could only build one house?"
"Exactly! We laid the foundation for the entire mountain. It counts as one house."
"..." Hasegumo looked at them skeptically. He felt like something was wrong with that logic, but he couldn't quite put his finger on it.
"Senpai, why are you back all of a sudden?" Haibara knew Nagasawa, though not well; he gave her a polite nod.
"I brought her back to pay respects to the old man." Hasegumo pointed to Nagasawa, then rubbed his chin. "Speaking of which... where's the grave?"
"Over there." Haibara pointed to a two-story building on the right. It was magnificent, shimmering with gold, and had no windows—only two large, closed doors. It looked more like a cathedral than a tomb.
"In ancient times, this would have been considered a total violation of imperial protocol," Hasegumo muttered, complaining about "feudal dross" while happily leading Nagasawa by the hand toward the site.
The Tombs of the Star Corridor.
A mysterious place said to require passing through a thousand doors to reach its heart. Only by arriving here can one meet the true shadow-ruler of the Jujutsu world, the cornerstone of all barriers, the "Living History," and the possessor of the Immortality Technique: Tengen.
Everyone in the Jujutsu world knows Tengen's name, but very few have ever reached the Star Corridor.
Not only is there the trial of a thousand complex doors inscribed with barrier techniques, but the entrance is also strictly guarded by Jujutsu High. Even Hasegumo had never been here.
But today, one week after the Hokkaido Incident, an uninvited guest stepped into this absolute sanctuary.
"What have you... come for?" Tengen sensed the unknown intruder immediately. Yet, the entity did not attack; it only questioned the intruder's purpose. It knew the visitor hadn't come to kill.
"To make a deal, of course. And also..."
Kenjaku leaned his head against his right hand. At the sound of the voice, he gently tossed a small cube with his left—a heavy, metallic object with several eye-like markings on its sides.
"...to bring you the Prison Realm."