Kai, Mei, Kitsuna, and Yuki were strolling leisurely through the academy courtyard. There were no responsibilities at the moment, so they were just chatting without any real purpose.
"Let's go somewhere after school!" Kitsuna exclaimed, her eyes sparkling with excitement.
"Like a picnic? Or just hang out a bit?" Yuki asked, tilting her head slightly to the side.
"Anything at alllll!" Kitsuna giggled, then cheerfully wrapped her arms around Kai's neck, pulling him closer.
"Lately, I've been feeling strange around Kai... My heart starts beating faster, and I feel warm inside... Am I falling in love?" Kitsuna wondered to herself.
She had been trying to get closer to him for a while now—gently, subtly, but persistently. She knew she couldn't draw Yuki's attention. So her touches were soft and fleeting—on his arm, his neck, even his chest—just enough for Kai to feel them, but not enough for others to notice.
But... while Kitsuna was working hard to create a tender closeness, Kai was experiencing something entirely different.
"It's her again... Why is she getting so close? Is this some kind of attack? DO NEKO PEOPLE EAT HUMANS???" he screamed internally. His knowledge of love was an absolute zero.
While his mind was falling apart, Mei nudged him lightly in the stomach with her elbow—their secret signal. He knew exactly what it meant: "Read my mind."
Kai muttered quietly, "Mind reading."
His sister's thoughts came through crystal clear:
"Let's go to the academy library... alone."
Since they hadn't found anything useful the previous day, they were determined to try harder today.
Kai smiled softly, then tried to slip away from the group.
"My sis and I are heading to the library," he said, casually, as if it were no big deal.
"Ohhh… have fun, sounds boring…" Yuki replied, turning on her heel and walking off in the opposite direction. "Kitsuna, you coming?" she added, glancing back over her shoulder.
"Nah, I'll go with them~" Kitsuna said, still wrapped around Kai's neck.
"Your choice." Yuki said flatly, not even waiting for a response as she left.
"Um…" Kai tried to come up with another excuse, but just then, Mei jabbed him in the stomach with her elbow again.
He muttered quietly, "Mind reading."
His sister's message echoed in his head:
"She can stay…"
But her gaze… was slightly lowered, and her eyes didn't shine like they usually did. In that disappointed expression, there was a subtle trace of sadness.
The trio started walking toward the library together.
As soon as they entered, they began browsing the shelves, moving through rows of old, dusty books.
"Why are we here, exactly?" Kai asked while flipping through a stack of piled-up tomes.
"We're looking for a new clue. That piece of paper will help us," Mei said, pulling a small, black piece of paper from her pocket.
Kai immediately started rummaging through the books, while Kitsuna finally let go of his neck… only to now grab his hand—gently, but firmly.
"Yo… this book looks pretty…" he said, pulling one out from the shelf.
It was a hardcover—dark blue, almost black, but with a hint of deep navy that shimmered when the light hit at the right angle. In the center was an engraved tree, its branches spiraling outward.
Tiny sparkles were scattered across the branches, glinting with every movement—shifting from icy blue to silvery white, like snow under moonlight.
Kai opened the book. His eyes landed on the first page… and he began to read.
"Once upon a time, in a world called Nytherra—"
He didn't get any further. A giggle slipped out.
"HAHAHA! Imagiiine naming your world Nythe—"
But he didn't get to finish his sentence, because Kitsuna immediately slapped her hand over his mouth.
"Shhhhhh! Someone's gonna hear you!" she whispered frantically, glancing around.
"What?" Kai mumbled through her hand.
"If someone hears you mocking it like that… you could get in serious trouble," she said quietly, then pulled her hand away.
"Why? I'm just messing around with some random book…" Kai replied, confused by her sudden seriousness.
Kitsuna's ears drooped slightly.
"Haven't your parents taught you anything…?" she asked, her eyes a mix of surprise and sorrow.
Kai blinked.
Kitsuna took a deep breath, like someone about to explain something that should never have to be explained.
Softly, almost ceremonially, she began to recite:
"In the beginning, there was but darkness.
Formless. Timeless. Breathless.
And above that void did hover She who hath no mother nor father,
who was neither born, nor forged—Nytherra, the First of All.
The Seed of Night and the Dawn That Breatheth Alone.
In the stillness without end,
Nytherra opened eyes that seeth even what is not.
And She spake—not with word, but with will that bendeth all things:
'Let there be a WORLD.'
And light did kindle within the bosom of shadow,
like flame sprung from no source.
And She shaped it with hands gentle, yet eternal—
rivers did She form, and lakes, and mountains also."
"So... she's like a god?" Kai asked softly, his tone now more serious.
"Not like, Kai… She is God!" Kitsuna said, clutching his arm even tighter.
"Being X," Kai muttered with a grin.
"What?" Kitsuna blinked, confused.
"Oh, nothing…" he waved it off. "So… she created the races too?"
"She did," Kitsuna confirmed with a nod. "Nytherra shaped all six races."
Kai turned to her with a soft smile.
"Thank you," he said gently, then slowly patted her on the head, his fingers gliding through her hair.
Kitsuna instantly let go of his arm and took a step back. Her cheeks flushed—her face dyed strawberry red.
"Kai… it wasn't anything…" she wanted to say, but… the words caught in her throat. She could only stand there, staring at him.
"He's so sweet… So… innocently sweet…" Her eyes widened like she was gazing upon a divine being. "I want to tell him. I want to tell him how much I love him…"
She took a deep breath. And then she stepped forward.
"Kai!" she called out, clear and loud.
He placed the book back on the shelf and turned toward her.
"I… I have something to tell you…" she said firmly, clenching her fists.
"I'm listening…" he answered softly, still confused.
"I… I lov—"
"Bro!"
Mei's voice shattered the moment.
Kai instantly turned toward her and walked over, completely unaware that he had just missed… one of the most important moments in a girl's life.
Kitsuna remained standing in place. Her arms slowly dropped to her sides. Her heart sank, and she lowered her gaze to the floor.
After a few seconds, she followed after him, trying her best to hide the disappointment.
"Did you find something?" Kai asked, watching Mei as she pulled a small black notebook off the shelf.
"Look! The corner's torn…" she said excitedly, pointing to the ripped edge of the cover.
"What do you need that for?" Kitsuna asked quietly, still confused about everything. She didn't know anything about the diary… or the theft.
But Kai and Mei didn't answer. They just kept going, completely ignoring her.
"Open it! Open it!" Kai urged, barely able to contain his excitement.
Mei carefully flipped through the pages. The first half of the notebook was empty… and then—numbers. No pattern. No logic. Just scattered across the pages.
"What do they mean?" Kitsuna asked again, but once more… nothing. Either they were too focused. Or—like so many times before—they just ignored her.
She stood there, watching them, a quiet ache spreading through her chest.
"This is harder than the Kira Case!" Kai shouted, grabbing his head dramatically.
"No, it's not!" Mei laughed, snatching a pencil. "Actually… it's super easy. Look."
She drew a single comma after the first number.
Kai blinked.
"Oh… yeah… Now I see it."
And the number became...
3.1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679 8214808651 3282306647 0938446095 5058223172 5359408128 4811174502 8410270193 8521105559 6446229489 5493038196 4428810975 6659334461 2847564823 3786783165 2712019091 4564856692 3460348610 4543266482 1339360726 0249141273
7245870066 0631558817 4881520920 9628292540 9171536436 7892590360 0113305305 4882046652 1384146951 9415116094 3305727036 5759591953 0921861173 8193261179 3105118548 0744623799 6274956735 1885752724 8912279381 8301194912 9833673362 4406566430 8602139494 6395224737 1907021798 6094370277 0539217176 2931767523 8467481846 7669405132
0005681271 4526356082 7785771342 7577896091 7363717872 1468440901 2249534301 4654958537 1050792279 6892589235 4201995611 2129021960 8640344181 5981362977 4771309960 5187072113 4999999837 2978049951 0597317328 1609631859 5024459455 3469083026 4252230825 3344685035 2619311881 7101000313 7838752886 5875332083 8142061717 7669147303
5982534904 2875546873 1159562863 8823537875 9375195778 1857780532 1712268066 1300192787 6611195909 2164201989
Kai stared at the sequence—and then it clicked.
"It's π!" he shouted, proud of himself for recognizing it.
"I'm surprised they even stopped," Mei added, continuing to recite from memory:
"3809525720 1065485863—"
"Okay, okay, we get it!" Kitsuna interrupted, rolling her eyes.
"But… what is π?"
They froze.
"…You don't know what π is?" the siblings asked in unison, completely stunned.
"No?" Kitsuna blinked, genuinely confused.
Kai groaned.
"What did they even teach you in school?"
"And how do you know π by heart?" Kitsuna asked, tilting her head.
"No, no, no… Kai memorized π. I'm just calculating the next digit in my head," Mei explained casually.
Kitsuna gave her a weird look.
"Never mind…" Mei waved it off. "Let's just open the secret door."
"Secret… door?" Kitsuna repeated, tilting her head.
"Yeah, it's right here!" Mei said, pointing at a bookshelf.
Kitsuna stared at the shelf, as if trying to open it with her mind.
While she was still puzzled—they already knew what to do.
Kai and Mei pulled two books at the same time.
Click
The shelf rattled, then slid back—and to the side… revealing a dark passageway.
Kitsuna was speechless.
"How… how…?"
"Seems like π doesn't even exist in this world," Kai muttered with a shrug.
Mei immediately launched into a breakdown, fast and clear:
"We had three theories:
1. Pull books 103,993 and 33,102
2. Pull books 355 and 113
3. Pull books 22 and 7
The books are numbered, so that made it easy.
We used the process of elimination. The first theory's out, since there aren't 103,000 books here.
That left two.
We picked the third—it's the simplest.
All of them are approximations of π, just with different levels of accuracy."
She took a deep breath.
Kai paused dramatically in front of the entrance.
"Ladies first."
He let his sister through…
But when Kitsuna tried to step in, he held out his arm—
—and slipped in ahead of her.
The tunnel walls, though old and crumbling, were laced with thin, vein-like lines—like roots or arteries. Some kind of bluish, glowing liquid flowed through them, shimmering like phosphorescent blood. The light it gave off was soft, but just strong enough to illuminate the entire hallway with a cold, otherworldly glow.
The bluish reflections danced across dusty surfaces and cobwebs hanging from the ceiling, turning ordinary spider silk into something that looked like strands of silver.
As soon as they stepped inside, the bookshelf that had acted as the secret door groaned loudly and began sliding back into place.
BANG!
The sound echoed through the stone, shaking the ground beneath them.
"How are we gonna get back?" Kitsuna asked quietly, a touch of panic in her voice.
"You claustrophobic or something?" Kai asked without looking back.
"Well… no… but…" Kitsuna mumbled, eyes fixed on the glowing veins slowly pulsing along the walls. Her heart was pounding faster now. She was scared—but trying her hardest not to show it.
They kept walking.
Their footsteps echoed on the stone floor.
At the end of the tunnel—
—a wall. Completely blocking the way.
"Fuck…" Kai muttered, scratching the back of his head.
They turned around and headed back.
The bookshelf—now the door—was still closed.
"What do we do now???" Kitsuna asked, her voice tight.
"Do we scream? Bang on the wall?"
Silence.
"Kai…" she tried again, but still—no response.
"Let me see that symbol again," Kai finally said, turning toward Mei.
She handed him a piece of paper.
Kai studied it, tilting his head slightly. The soft blue light shimmered across his face.
"You know… this looks like an eye…" he muttered. "Maybe I have to gouge mine out…"
Without hesitation, he raised his hand to his eyelid.
SMACK!
Kitsuna slapped his hand away.
"What the hell are you doing?!" she half-squealed.
"Taking out my eye," Kai replied flatly.
He tried again.
SMACK!
"No," Kitsuna said firmly.
He moved again.
"No..." she repeated, sharper this time.
With a sigh and a dramatic eye roll, he lowered his hand.
"So now what?" Mei asked, glancing around—at the walls, the glowing veins… searching for some kind of hidden clue.
The blue light kept pulsing—soft, steady, mysterious.
"I don't know…" Kai murmured.
Ten minutes passed.
And they were still standing. In silence.
Another ten.
No movement. Just deep sighs.
After another ten, they all slowly sat down on the cold stone floor.
Kitsuna stared at the ground. Her heart was pounding like crazy. Her tail twitched anxiously, and her ears drooped almost all the way down to her eyes.
She took a deep breath.
She knew this might be her only chance.
If they stayed trapped here… at least she wanted to say it.
"You know…" she spoke softly—barely above a whisper.
"If we're really gonna die down here… then there's something I have to tell you, Kai."
Kai and Mei looked up at her.
His face—confused.
Hers—sharp, like someone was trying to steal the most precious thing she owned.
Kitsuna hugged her knees to her chest and clenched her fists.
"Well… um… Kai… lately I've… started developing feelings for you…" she whispered, ears folding completely.
In that moment...
Mei's eyes blazed with fury.
Her fingers curled into tight fists, nails digging into her palms.
Her heart pounded violently in her chest—pure frustration.
"I swear to god I'd love to break her jaw right now…" she thought. "Who does she think she IS??"
Kai just stared at Kitsuna, completely lost.
"Um…" he mumbled.
Mei bit the inside of her cheek so hard it almost bled.
Through clenched teeth, she hissed:
"Spell it out for him…!"
Kitsuna flinched.
She looked at Mei.
She didn't know what hurt more—that glare full of hate… or Kai's total confusion.
"I love you!" she declared, firmly but sincerely.
Her eyes sparkled, but they were wet.
Kai turned to his sister.
Then to Kitsuna.
Then back to Mei.
And then again to Kitsuna.
"You mean love… like… love love?" he asked, clearly struggling to process it.
"Yes!" she said with a shaky smile.
Her voice trembled, but she was doing everything not to cry.
Kai blushed. His eyes dropped.
He looked at the floor, quietly.
And Mei...
...Mei was biting her lip so hard it was nearly bleeding.
She didn't know whether to scream—
—or to grab Kitsuna by the hair and throw her through the tunnel wall.
A moment later, Kitsuna decided to share something more with them.
"You know, I had a pretty boring childhood.
I mean—it was always fun for me, because I believe fun is like, the most important thing in the world… but yeah. Not much happened.
I grew up with my mom, dad, and my older brother—who always thought he knew everything.
And maybe he did… but I knew how to annoy him. Teehee~
But now that I've come to the academy and met you guys… it feels fun again."
She paused, then grinned wider.
"The only thing I still want… is to become a legend.
But not some tragic heroine with tears in her eyes—ugh, nooo.
I want people to talk about me with smiles.
Like, when someone says 'Kitsuna,' I want them to instantly think of pranks, tricks, and… that one crazy fox girl who never knew when to quit."
Kitsuna spoke with a bright smile on her face, her fox tail swaying side to side in rhythm with her joy.
"But now that I'm with you two, I'm really having fun. THANK YOUUU!!!"
The siblings smiled—perfectly in sync.
"We're glad!" they said at the same time.
But then, the sister leaned in slightly toward Kitsuna, her sweet smile dripping with possessiveness, and added:
"But don't even think about stealing my brother."
"Don't worry…" Kitsuna muttered, glancing away, her ears drooping.
SHHHHHHH! TRRRRRR!
The sound of heavy stone scraping across the floor sliced through the air.
They all turned sharply.
The massive rock that had blocked their path was now sliding aside—revealing a hidden passage behind it.
Without saying a word, they stood up and walked toward the opening.
In front of them…
...a spiral staircase, descending deep into the underground darkness.