Night settled quietly over the island.
The sea breeze rolled in with a damp, salty scent, brushing across the sand as the campfire painted their faces in warm, shifting light.
Aoyama bit the last piece of grilled fish from its skewer, chewed, swallowed, then picked up a split coconut shell and took a long drink.
The sweet liquid slid down his throat, cool against the heat lingering in his chest.
“That hits the spot.”
He leaned back against a jagged reef stone and looked up at the sky.
The moon had only recently risen, spilling silver light across the ocean.
Waves folded onto the shore in steady rhythm, unhurried, like some ancient pulse that belonged to the island alone.
“Aoyama-kun.”
Kasumigaoka Utaha sat a short distance away, knees drawn up, arms wrapped around her legs.
Firelight brushed her profile in amber tones, and the night wind teased strands of black hair loose against her cheek.
“Hmm?”
She turned toward him.
The flames reflected in her red eyes, flickering softly.
“While we were eating, I was thinking about your Underwater Breathing ability.
Does it still affect you when you’re breathing normally?”
Aoyama considered that and swallowed the last of the coconut juice.
“Part of it probably stays active.
My lungs regulate tension better now.
Even when I’m breathing normally, oxygen exchange should be more efficient than before.”
“No wonder.”
“No wonder what?”
Utaha rested her chin on her knees, gaze drifting toward the fire.
Her tone carried that familiar hint of amusement.
“No wonder you’ve been staring at me for the past seven seconds without your heartbeat speeding up.”
He blinked.
“You can hear my heartbeat?”
“Of course not.” She arched a brow.
“But you were looking at me from this distance for about seven seconds.
Most boys would have at least a slight change in their breathing.”
Her lips curved.
“You, on the other hand, were steady as still water.”
“Maybe that’s Environmental Adaptation at work.”
“Oh?” She tilted her head.
“So you’re adapting to me?”
Her voice lowered, the final syllables stretching playfully.
“Or do you want me to adapt to you, Aoyama-kun?”
Before he could react, she leaned closer and caught him off guard, her hand closing around him.
He went silent for half a second, set the coconut shell down in the sand, and sighed.
“Where did you learn that kind of trap question?”
“Self-taught.” A faint blush rose to her cheeks, though she lifted her chin with mock dignity and brushed windblown hair behind her ear.
“And is it really so embarrassing to be seen through by me?”
She sounded calm, but her fingers told another story.
She could barely wrap her hand around him.
That shouldn’t be possible.
And yet Aoyama was clearly holding himself back.
“It’s not embarrassing,” he said.
He nudged a piece of wood in the fire with a stick.
Sparks lifted into the air, brief constellations that vanished almost instantly.
“But when you observe that closely, it does make me feel a little pressure.”
“Pressure?” Her grip faltered slightly.
Was I too tight?
“I’m worried that one day I’ll breathe a little heavier and you’ll interpret it as some strange psychological development.”
Her voice flowed gently through the dark.
“Don’t worry.
I only interpret the parts I want to.”
She glanced up at the moon as if distracted, then tightened her hold deliberately.
Silence stretched between them, broken only by the crackle of burning wood and the steady hush of the tide.
After a while, she spoke again, softer now.
“When you’re underwater, you can’t talk at all, right?”
“If I talk underwater, I swallow water.”
“So you’re completely silent down there?”
“More or less.”
She buried her face against her knees, voice muffled.
“That’s a shame.”
“A shame?”
“Nothing.” She lifted her head, one side of her flushed face caught in firelight, her eyes bright with something restless and warm.
He studied her profile, softened by moonlight and flame.
“Then next time I’ll try evolving the ability to talk underwater.”
A laugh escaped her before she could stop it.
The smile in her eyes deepened.
“When you say things like that with a straight face, it sounds like you’re telling a deadpan joke.
It’s… kind of cute.”
“Is that a compliment?”
“You tell me.”
He didn’t press further.
Instead, he focused on the fire and on the subtle shifts beneath her touch.
A few minutes later, he felt a light weight settle against his shoulder.
Utaha had moved closer without him noticing and leaned her head against him.
Her hair brushed his neck, carrying a faint fragrance he could not quite place.
Somehow, even on a deserted island, she still smelled like herself.
“Aoyama-kun.”
Her voice was so close that her breath grazed his ear.
“Yeah?”
“If it were just the two of us on this island, wouldn’t that be nice?”
He thought for a moment.
“Given the current circumstances, yes.”
She let out a soft laugh.
“In a normal school romance, the heroine would probably call you dense for answering like that.”
There was one thing she did not say aloud.
Aoyama was not dense.
Not when there was a very heated piece of evidence proving otherwise.
“Would you say that?” he asked.
She nudged his shoulder lightly with her nose.
“I wouldn’t.
I know you’re not dense.”
He said nothing.
His arm rose naturally, slipping around her back to rest on her far shoulder.
The movement carried no hesitation, as if he had decided on it long ago.
After resting against him for a while, she tilted her face up.
Moonlight brightened her eyes.
“Aoyama-kun,” she said, her voice softer than usual, threaded with tension.
“Your breathing changed again.”
“Did it?”
“It paused for a beat just now.
Very brief, but I felt it.” Satisfaction flickered across her lips.
Her method was clearly working.
He looked down at her.
“I guess I can’t hide anything from you.”
“Of course not.” There was pride in her tone, but her eyes held something gentler.
“So was that because you were nervous?
Or were you thinking about something else?”
He was quiet for two seconds.
“Both.”
She didn’t push further.
Instead, she tucked her face back against his shoulder, settling into him as if she had found the perfect place.
The wind shifted, pressing the flames low before they sprang up again.
Much later, her voice returned, light but irreversible.
“Aoyama-kun… it’s okay.”
He stiffened slightly and looked at her.
She didn’t lift her head, though the tips of her ears were faintly pink.
“It’s just you and me on this island.
And tomorrow you’re diving back down there again.”
She paused, swallowing something unspoken.
“We should at least leave some…”
“Leave some what?”
She raised her face at last.
The fire painted her expression in gold and shadow.
Composed as ever, yet her eyes shimmered faintly.
“Leave some proof,” she said.
“Proof that you were with me tonight.”
He looked at her for a long moment, so long the fire seemed to shrink between them.
Then he reached up and brushed her wind-tangled hair neatly behind her ear.
Her earlobe was warm beneath his fingers.
She turned her face slightly, flushed, but did not pull away.
When he reached toward his backpack to search for protection, she stopped him.
“Aoyama-kun, for the first time… we don’t need that.”
The spark inside him flared instantly.
Still, he did not rush.
He moved carefully, testing, waiting, until the moment unfolded naturally and he entered her.
“Utaha, relax.”
“Mm…”
She bit down softly, face flushed, breath trembling.
The fire crackled under the night sky, their shadows shifting together across the sand.
He adjusted their position so she sat with her back against him, his chin resting lightly atop her head.
Her back felt the steady strength of his heartbeat.
“Your breathing changed again,” she murmured, voice thick, rising slightly at the end.
“It sped up a lot.”
“And you caught that too.”
“Hard not to.”
She leaned her head back against his shoulder and looked at him sideways, mischief glinting in her red eyes.
He bent and pressed a light kiss to the crown of her head.
“You’re Kasumigaoka Utaha.
Nothing gets past you.”
She laughed softly, the sound carried away by the wind.
Her gaze drifted toward the silver path of moonlight stretching across the sea.
“Aoyama-kun.”
“Yeah?”
“You can really stay underwater for twenty-five minutes?”
“In theory.
Probably longer in practice.
Environmental Adaptation helps.”
“Then when you come back up…”
She hesitated for so long he thought she might stop there.
“When you come back, I’ll give you more surprises.”
“And you have to hold me like this again.”
His arms tightened around her.
“Okay.”
The answer came easily, like confirming a promise already made.
She closed her eyes, her breathing gradually losing its rhythm.
The fire burned low as the night deepened.
“Aoyama… slow…”
The waves continued their endless murmur while the wind slowly erased their footprints in the sand.
He sat in the fading glow, one arm wrapped around her waist, his palm resting against her lower abdomen, warm and steady.
He lowered his head and whispered something by her ear.
She didn’t open her eyes, but a faint smile curved her lips.
Moonlight bathed them both, and the endless ocean behind them.
When she finally reached her peak, her legs trembling uncontrollably, she gasped, “Aoyama-kun… inside.
Not outside…”
He frowned slightly.
It was not the wisest choice.
But it was what she asked for.
So he complied.
“Aoyama-kun… again…”
The night was still very long.