Episode 7: To the Depths Below

"Sleipnir, commencing submersion."

The hull lurched, and seawater slammed against the windows. The sensation of sinking into the depths of the ocean. The engine roared as it carved through the vast sea. Into the transparent underwater world, Sleipnir descended.

"...Whoa, amazing."

"Ka-ka-ka! Of course! This one is magnificent!"

Sleipnir's delighted voice echoed through the cramped cabin. Yes, magnificent. Truly magnificent. But still.

"...Can't we do something about how cramped this is?"

There was only one seat inside Sleipnir. It was probably designed as a single-seater originally. Mef and I were crammed into the narrow space, awkwardly gazing outside.

"P-please move a little more that way."

"S-sorry."

Mef's legs were long, so she looked particularly uncomfortable. The scent of citrus drifted from her hair. And, and, something soft was—gnngh, mind over matter...!

(I wonder what happened to Luna-san after that...?)

Koito-senpai had noticed Luna's disappearance and was contacting someone. I hoped she'd managed to escape.

"Wow... so pretty... There's so many little fish... Oh, a batfish."

A school of small blue fish drifted alongside the submarine. Sleipnir's systems were projecting external footage onto the displays. Depth: 50 meters. Excellent water clarity. The submarine aimed for the world below.

"!"

Beneath us stretched the endless ocean floor. The deep blue where even light couldn't reach looked like a massive hole that could swallow everything.

(We're heading down there!)

A jackfish with a large head crossed our path. Its eyes showed neither sadness nor anger.

"That's a giant trevally."

"Mef, you really like fish, huh."

"...Not particularly. It's not like that."

I didn't even need to read her mind—her sparkling eyes as she watched outside made her feelings perfectly obvious.

"It's getting colder."

When we'd first boarded, Sleipnir had been hot and humid like a sauna (I'd flinched at the sensation of Mef's sweat against my skin), but now the seawater was cooling the interior.

...I'm a little scared.

Mef was frightened. The vastness of the ocean seen from a hill felt distant, like someone else's concern. But the vastness of the ocean felt from within it was terrifyingly immediate—its endlessness was unmistakable fear.

"—Mef! We have surpassed 200 meters!"

200 meters depth. —This was where the classification of 'deep sea' officially began.

"Sleipnir. The floodlights."

When Mef operated the control panel, the lights outside intensified—but they were immediately swallowed by the darkness of the deep, making it seem pointless.

"Heey. Mef-senpai. Kotoyorozu-san. How's it going over there?"

Koshiba's voice came through Sleipnir's underwater optical wireless communication.

"R-value is 0.99. Naxa Index is 82.4."

Mef read off Sleipnir's instruments.

"Almost the same as surface conditions! Contact us if anything changes!"

This cold, black world was the same as the surface? When the communication with Koshiba ended, only the roaring of the engine remained.

"We have reached 1,000 meters!"

How terrifying—and beautiful—the deep sea was. The thought came unbidden. In this world of faint light, life persisted. Solitude was fear, but it was also beautiful.

"Mef. What's the R-value and stuff you mentioned earlier?"

"The R-value measures how stable reality is. The Naxa Index measures how easily it fluctuates."

"Reality... has stability?"

"The more broken reality becomes, the more favorable conditions are for things that aren't real."

I see? So changes in R-value tell you if something abnormal is nearby? Mef didn't try to explain any further.

"Mef! Something approaches from the north! Likely a large creature!"

"Acknowledged."

Mef and I looked at the left monitor simultaneously. There was definitely something in the depths of the deep sea. As we stared—it suddenly appeared.

"I know that one. It's a hammerhead shark!"

A hammerhead shark. I'd seen one on TV before. A shark with a head shaped like a hammer—not a ferocious species that attacks humans.

"...Huh? But we're already about 1,200 meters deep. This shouldn't be its habitat—"

The hammerhead shark passed alongside Sleipnir.

"—Huh?"

"—It's huuuuuge."

It was nothing like the cute size I'd seen on TV.

"That beast be at least 50 meters in length!"

Its eyes, protruding from either side, passed us without so much as registering our presence.

"R-value is 0.97. Naxa Index is 80.2."

"...It went down a bit from before?"

"It's fluctuating significantly. This is proof that we're—approaching Anti-Reality space."

We continued descending into the darkness.

When I came to, a terrifying amount of time had passed.

"—Huh?"

Wait. What time was it? I checked my watch.

"Mef... Mef!"

"Huh? Wha—"

"We've been diving for eight hours!"

Mef's eyes had been vacant, but at my words she snapped back to awareness, her voice rising.

"No way. How has so much time—Sleipnir!"

"Hmm. It seems we are in a dangerous situation. Depth—205,000 meters."

"That's... surely a malfunction?"

Since when had we lost consciousness? Mef slapped her own cheek.

"I'll contact Koshiba and the others."

I pressed the switch for the underwater optical wireless communication.

"Wha... Finally... got a response... back. We were... just about to... use Shamshir... you know."

Koshiba's voice was cutting in and out. The environment must have been affecting communications.

"Continuing the operation."

"Roger! We'll extract you if we detect any vital abnormalities!"

We gave Koshiba a brief report and ended the communication.

"Did it say 200,000 meters deep? Does such a place even exist on Earth?"

"Even the Mariana Trench, the deepest point on Earth, is only about 10,000 meters."

So no matter how you looked at it, this situation was impossible.

"Sleipnir. Is the water pressure okay?"

"Aye. By rights, this one should be crushed by such pressure. Strangely, there are no operational issues. The laws of this ocean have likely been significantly rewritten by Anti-Reality."

Outside the windows was pitch black—nothing visible at all. A deep sea where not even a fragment of light could enter.

"...! Mef! Perhaps this one has malfunctioned after all!"

"Is there a problem with the submersion capability?"

"No! This one's radar is detecting something—but what is it?! Unbelievable!"

"Explain the situation in detail."

"At least thirty kilometers long!"

"Thirty kilometers of what?" Mef murmured. Sleipnir shouted.

"—A creature! A creature over 30 kilometers long is heading our way, it is!"

The cabin rattled and shuddered. We were being tossed about by tremendous currents.

"Sleipnir! Increase speed!"

With a great roar, Sleipnir surged forward.

"30 kilometers!? That's impossible for any living thing!"

"Abyssal Gigantism."

"Huh?"

"In the deep sea, food is scarce, so creatures take longer to mature. In exchange, they keep growing larger indefinitely. That's Abyssal Gigantism."

Even so, there had to be limits!

"There's no food in the deep sea. —Which means we're prime targets right now!"

Sleipnir's engine screamed. But the distance between us and it was clearly shrinking.

■■■■

—A voice. It was calling to me.

"Mef! That way. There's a cave over there!"

"What!?"

A pull of consciousness was directed at me from the direction of the cave. It wasn't just one or two.

(What the hell are these things!?)

It was the thoughts of countless humans—too many to count.

(Why are there so many people at the bottom of the ocean!?)

The emotion was stronger than anything I'd ever felt. My head felt like it was splitting open.

"Gaaaah!"

"Kotoyorozu-kun!"

"F-forget about me... Head straight that way!"

The submarine carved through the pitch-black world like parting the darkness itself.

A massive rock wall with an equally massive cavity.

OOOOOOOOOOOOOOOOOON

A sound like the ocean itself groaning. That was surely the monster chasing us.

"Entering that hole!"

With a tremendous roar of the engine, we raced through the deep sea.

We had been traveling through the undersea cave at 200,000 meters for about six hours now.

"Mef. You need to eat or you won't last. Here, I opened a can for you."

"...Thank you."

What an endless cave this was. We'd been moving for so long, but Sleipnir's floodlights still hadn't illuminated its end.

"Shouldn't I be asking if you're okay? You look really unwell."

From deep within the cave, a horrifying number of screams were begging me for help. Exposed to them constantly, I felt like I might throw up at any moment.

But the thought of vomiting in this cramped space—I didn't even want to imagine it!

"...Mef, why did you join Azure Academy?"

I needed to think about something else to distract myself. She considered the topic I'd squeezed out for a moment, carefully choosing her words before speaking.

"I... My father was a doctor and an occultist."

"Occultist?"

"Ah. At Azure Academy, they call it Miracle Theory. Essentially, it's things like incantations and such."

In other words, to put it in terms even an idiot like me could understand—

"A wizard?"

Mef snorted at my idiotic remark.

"It's not that glamorous. Though I believed in such things as a child."

"Huh... that's actually kinda cute."

"Cu—"

She fixed me with a glare from those sharp, upturned eyes.

"Kotoyorozu-kun. That habit of yours is not good."

"Huh. What is?"

"I-I mean... saying things like 'cute.' Saying things you don't mean."

Her reaction made me realize what I'd done.

"S-sorry. Did I upset you?"

"...Yes. You did. Quite considerably, in fact."

"I've always had this thing where whatever I think just comes out of my mouth."

(Since he can hear everyone's thoughts, he has no way of hiding his own.)

"Meep!"

Face flushing red, Mef jerked back and banged her head in the cramped submarine.

"...Myaaah..."

"Ooh, surprisingly clumsy. Cute."

"Wha—again! No! I'm not like that!"

She glared at me resentfully.

He said cute again!

And that thing about saying whatever he thinks...

What does that mean? What is he trying to say!?

Crap. I'd really flustered her.

(Is my complete lack of skill with girls showing!?)

Just because I could read minds didn't mean I had good communication skills. Those were separate issues entirely.

"A-anyway... So my father was secretly an occultist, and he caused a terrible Anti-Reality disaster and was captured by the Illuminati."

"What an eventful life."

"My father spent several years in prison and was released. My brother and I were placed under protection in District 12 during that time... Since then, we've officially lived in that city, and I enrolled at Azure Academy."

Mef had led quite an adventure-filled life herself. Well, you wouldn't end up 200,000 meters underwater otherwise, I supposed. I couldn't help but smile a little.

"! Look at the instruments."

Mef's expression turned grave as she pointed at the readings.

"What? Ah, the R-value... it's dropped again!"

"R-value 0.89. This means where we are now is—closer to fantasy than to reality."

"What's going to happen?"

"Anything at all."

This was a place where the laws of the universe didn't work properly, she said. But with the view still pitch black, it was hard to grasp what that meant. Yet I would understand soon enough.

"Mef! We are breaking through the water!"

"...What?"

That was impossible. According to the instruments, we should still be in deep ocean.

"Behold! That is the surface! Behold—light! The radiance of the moon!"

Splash! Sleipnir burst up from the depths of the ocean and broke through to open air.

"No way. What... is that?"

Sleipnir opened the hatch. Viscous air brushed against my cheek.

Beneath a starless sky where two moons crossed paths.

—A massive hulk of machinery hung its head in eerie silence.