Extra: That's some pretty deep conversation

① Kai Sagami survival what-if route

I, Haruka Itadori, and Kai Sagami had finally survived that nightmarish mission. At the very last second, I had mastered and activated Domain Expansion, something like the ultimate expression of a Cursed Technique, and that was how we had made it through unscathed.

"That was close. I thought we were going to die."

"Please don't make me remember it."

A week had passed since then.

Our teacher had checked in on us, and we had been given a short vacation. What we would do with that free time... was already decided.

"It's so hot~. What a pain."

"Who was it that said we should go to the beach...?"

"You and me."

"Right. I feel like I'm going to die."

Whoosh, splash. Listening to the waves wash onto the beach and retreat, we both hung our heads.

Summer was almost over, but thanks to global warming, the lingering heat was unbearable. We indoor types had been utterly defeated by the scorching sun.

"Are Yuji and Junpei still not back...? They said they were buying drinks."

"Come to think of it, Satoru Gojo's gone too."

"...Don't tell me someone's hitting on them," we said together.

We waited under the beach umbrella for the parental contingent, enjoying nothing but conversation. Playing in the sand meant the hassle of getting it under our nails, and going into the sea meant someone with a constitution like mine might get swept away. So, averse to trouble as we were, we waited without moving a single step.

"Ah~. It's so hot. I can't take it. I'm dying~. I'm going to turn into a dried-up earthworm~."

"Kai, that's a pretty understated comparison, but it's way too real..."

How many dried-up earthworm corpses had I seen on the asphalt on my way to and from elementary school, and how many times had I imagined myself in their place? Apparently, my friend beside me pictured it too when he heard that, because he shuddered.

"...That's some pretty deep conversation."

Suddenly, a voice came from above the beach umbrella.

Of course, we only knew one person that tall with such a nice voice. Still, we had to look up.

"Mr. Gojo." "...Oh."

"Wow, you look half-dead. Weren't you the ones who wanted to come to the beach?"

The umbrella blocked his face, leaving only his muscular upper body, swim trunks, and absurdly long legs visible.

Realizing there was no point in looking, I buried my face in the sand again and muttered.

"Not everyone has a brain wired for youthful fun like you guys."

I had known Yuji and Mr. Gojo would have a great time, but I hadn't expected Junpei to join them. My partner had taken him by the hand, and they'd jumped into the sea together. Ah, youth.

"Or maybe Haruka and Kai just act like old men?"

"Do we?" "Please call us indoor types."

Kai and I denied it in unison, giving him dead-fish stares.

"Well, if being young means having a bunch of girls crowd around you squealing, I'm fine with acting like an old man."

"Same here on the right. If being young means picking up girls while saying things like, 'Using Cursed Techniques on ordinary people is forbidden~,' I'm fine with shriveling up into an old geezer."

It wasn't as if we envied him for getting hit on. Nor was it our business how many hickeys he was deliberately showing off.

"Still, that's not a great look for a teacher," I whispered.

"Yeah. That's Satoru Gojo for you: great face, great income, terrible personality," he whispered.

"I can hear you, you know!? And you two really are close!?"

Apparently, Mr. Gojo had heard our whispers, because he called us out. Kai and I kicked hard at the head he poked in beneath the umbrella.

"Of course we are. We're best friends, aren't we?" we said together.

My brother, who appeared at the edge of my vision, looked down at the man we'd kicked over into the sand.

"You're acting pretty youthful yourself."

He muttered it in an exasperated voice.

A little later, Yuji and Junpei came back. Both had their arms full of colorful juice drinks and were wobbling toward us. Were those drinks going to be okay?

Just then, Kai, who had been sprawled beside me, got up, sprang to his feet, and jogged across the unsteady sand toward them. He seemed to step on a shell or something on the way and cried, "Ow!?" but still made it over to them. Then he took the two cups Junpei was carrying.

"...Oh? Helping carry things? What a good kid."

Mr. Gojo, who had somehow settled down beside me as if he belonged there, muttered that.

No, even a teacher shouldn't be using his students as errand boys, right? Wasn't that an abuse of authority?

I glared at him with dead-fish eyes, but he was already completely in vacation mode, and our kick had left him covered in sand. It didn't seem right to talk work with him either. I only snorted in response.

When I looked back, Junpei and Kai seemed to be discussing something. Both looked a little reserved, while Yuji smiled wryly beside them and smoothed things over. Maybe their temperaments were similar; despite their politeness, they seemed to be enjoying the conversation.

Propped on my elbows in the sand, I watched them and muttered again, "It's hot."

I slowly got to my feet too, frowning at the sticky feel of sand against my soles. Our teacher looked up at me.

"Huh? Even Haruka's going to help for once?"

What a rude question. Unfortunately, the answer was no.

"Kai, I'm heading over there for a bit."

Floating was the only thing I was good at.

Bubble, bubble. Drift, drift.

The cold seawater felt pleasant against my skin. The waves pushing me out to sea rocked me gently, giving everything an unreal feel.

"...Hot and cold at the same time. I don't get it."

My back and the inner sides of my arms and legs were cold where they touched the water, but my exposed upper body was roasting in the sun. I'd made a rare trip to the beach and was only getting half the cooling effect. It felt like a rip-off...

Thinking about that, I stared blankly up at the sky.

The sun hung high in the vast, clear blue sky. There was no trace of the dawn colors branded into my terrifying inner landscape. A little relieved by that, I sighed and let all the strength leave my body.

A version of the backstroke without moving your arms or legs... I called it the sea otter stroke. It was my specialty, so it wasn't tiring at all. I really was simply floating. As always, I went completely limp and drifted on the surface.

There was a silly little reason why I was soaking in the sea now, after refusing to go in because it was too much trouble.

"...It's not envy. It's jealousy."

Simply put, I was jealous that Kai was talking to Junpei Yoshino. That was all.

Just as I was Kai's first friend, Kai was mine. We'd grown close over the month or so we'd spent together, but I wanted us to hang out more, to share more fun together. And just as I was thinking that, I'd seen that scene... so yes, I was probably sulking.

Like a child throwing a tantrum after having his toy taken away. I'd never realized I had such a childish side.

I'd tried going into the sea to cool my head, but...

"It's just not the same as the real thing."

Kai the human, and the sea, a giant puddle. They shared the same character in Japanese, but the comfort and reassurance they gave me were completely different.

When I was with Kai, I could let my guard down completely and feel safe. Even silence felt like a wasted opportunity, so I would talk. I wasn't much of a conversationalist either; sometimes there were stretches of silence, and sometimes I said things that made no sense, but it felt good that way.

I happened to glance up.

I saw purple gradually bleeding into the blue sky.

"...I should probably stop sulking and head back."

Just as I thought that, a foolish little "Oh" escaped me.

Come to think of it, how am I supposed to get back?

Since I was only floating and not doing any actual swimming, there was no way I could get back to shore on my own.

"...What do I do?"

Did this count as being mildly stranded? And where exactly was I going to get swept off to?

I'd been so busy relaxing and floating that I'd simply drifted farther and farther with the waves. I hoped someone on the beach would notice, but I'd already floated quite a distance away. Maybe no one would.

I was thirsty and hungry too. I wanted to head back soon.

But rather than going back and seeing Kai having a lively time with Junpei and Yuji again... maybe staying here and floating wasn't so bad.

"Hmm~."

Seriously, what do I do?

Just then.

I heard water splashing. The surface rocked sharply, sending up little waves.

Then a shadow fell over me.

"...What are you doing, Haruka?"

"...Kai?"

Looking down at me was my best friend's face.

He stood in water up to his chest, looking down at me with a somewhat baffled expression. In his hand... for some reason, he held a rope.

"Sorry if you thought you were stranded, but you're still in the shallows, you know?"

The blue rope blended so subtly into the seawater that it was hard to see, but on closer inspection, I could make out its end tied around my ankle.

"Huh?"

I blinked, still not understanding what was going on. He awkwardly averted his eyes and stumbled over his words.

"~Well~."

"?"

"I'm saying! I was worried you'd wander off, so I tied a Cursed Tool to you as a safety leash!"

"..."

Honestly. My best friend had decided I would get lost-a certainty-and put a safety leash on me, worth several hundred thousand yen at market price.

In that case, no matter how far the waves carried me, I wouldn't get stranded. It also explained why I'd stayed in the shallows the whole time. Wait, had I been wandering around on a leash this entire time? How embarrassing.

But more importantly...

"Thanks for worrying about me."

That was all I said.

Kai pouted and continued complaining.

"Seriously, when you weren't under the umbrella, I freaked out. You made me accidentally send Satoru Gojo flying with a kick."

"What were you doing?"

"He's a useless teacher who can't even keep an eye on Haruka."

"True," I replied with a wry smile. Then I dipped under the water once and properly planted my feet this time.

The gritty feel of the sand was unpleasant after all, and the seawater was a little too cold.

"Come on, let's head back. I went to get you a drink for once, and now it's gone warm."

I took his outstretched hand and gripped it tightly.

"Oh. I thought you were chatting with Junpei."

"No. We were discussing switching hotel rooms. The original sleeping arrangements were Yuji Itadori with Haruka, and Junpei Yoshino with me, right? I was asking if we could swap."

I blinked at the unexpected topic of their conversation.

I felt my face grow hot at how badly I'd misunderstood.

"It's hot..."