On the JR Tokaido Main Line's special rapid service bound for Ogaki, a petite girl named Nukumizu Kaju holds onto the handrails as the train sways. Despite being alone on the train, she doesn't hide the excitement in her eyes.
—Indeed, she's on her way to a date with her beloved older brother.
While she has been out with other girls before, she adamantly refused to label those outings as dates. However, this time, the term "date" is unmistakably present in her brother's smartphone search history.
By searching for "Taketakeshima Aquarium," "first time," and "what kind of clothes," she easily discerned the location and situation of the date. The date's date and time were also confirmed from the weather forecast and transportation search history.
In anticipation of this day, she brought out the "clothes that suit her older brother," recommended by her father, and flawlessly put together an outfit for the date.
The only thing Kaju couldn't figure out was the date's partner. She subtly probed Yanami and others, but there seemed to be no indication from them. Komari or someone from the student council remained as potential candidates, but there was also the possibility of someone unknown to her.
After all, it's her older brother. The women of the world wouldn't overlook his charm.
An announcement echoes inside the train. With a travel time of a little over 10 minutes, they would soon reach Gori Station.
"...First, I'll see it with my own eyes."
Kaju tightens her expression as she steps onto the platform. Contemplating the upcoming plans, she descends the escalator.
—By now, her older brother has likely arrived at the aquarium.
Picturing his figure, she passes through the ticket gate, and there stands a petite girl clad in a yellow parka, short pants, and a vibrant green backpack.
"...Could it be Komari-san?"
"Eh?! K-Kaju-chan? W-Why are you here?"
Bending down and freezing in place, Komari is approached directly by Kaju.
"So, Komari-san is my older brother's date! That outfit is incredibly cute! Is this the kind of clothes he likes?"
"N-No, these are hand-me-downs from relatives—"
"If that's the case, my brother is sure to fall for you!"
"I-For me...?"
As Komari's eyes dart around in confusion, Kaju pushes closer, bombarding her with questions.
Furthermore, just as Kaju is about to say something, a familiar voice is heard from behind.
"...So, Nukumizu-kun, it's a date after all."
When Kaju turns around, there is Yanami Anna.
With an exaggerated gesture, she sweeps her hair back.
"Yanami-san?! Uh, wait, isn't today my brother's date with someone else—"
Cutting off Kaju, Yanami smiles knowingly.
"Something seemed off about Nukumizu-kun on Friday. Lemon-chan was acting all secretive, and your sister even asked about Sunday's plans and the aquarium."
"...Um, more importantly, why are both of you here?"
Yanami moves forward, walking towards Kaju.
"Indeed, we're here for the same reason as your sister, Kaju-chan. We understand your feelings."
"Huh?!"
Yanami takes hold of Kaju's hands and speaks with a cheerful tone.
"We've come to ruin your date!"
...No, that's not it.
Kaju tries to respond immediately, but the words get stuck in her throat.
Yanami smiles gently, as if to say not to say anything.
"We can't let you have a date without us knowing. We need to monitor it properly."
Yanami winks at Kaju.
"But, little sister, while we understand your feelings, I think disrupting it might be going a bit too far."
...Disrupting the date.
She never thought about such a thing, but why couldn't she deny it?
She just wants to etch her brother's appearance into her heart as much as possible.
While suppressing her confusion, Kaju calmly inquires.
"Um, why are you two monitoring the date...?"
Yanami casually responds.
"Because it's against the rules of the Literature Club—no dating allowed!"
"Uh?!"
In the chaos near Gori Station's ticket gate, where the announcement echoes, a new voice adds to the confusion.
"Oh, is she Nukumizu-kun's sister? Did Yanami-chan invite her?"
The fourth character to appear is Tsukinoki Koto, the former vice president of the Literature Club.
He enters while casually twirling the car keys with his fingers.
"We ran into each other here. It seems your sister came to monitor Warm Water-kun as well."
"So, the date is real. That girl is quite something."
Kaju resigns herself halfway and reconstructs today's schedule in her mind.
Rescheduling complete in her mind, she takes a small deep breath, bows her head to Koto, and says,
"It's been a while since the Tsubaki Festival. Did you come to observe my brother's date, too, Tsukino Koto-san?"
"I don't really get it, but it seemed interesting, so I tagged along!"
Ah, that's the kind of person he is.
Glancing around, Yanami is looking around restlessly.
"Little sister, is Nukumizu-kun coming soon?"
"He should be on a train earlier than mine, so he's probably already at the aquarium by now."
...The plans changed a bit, but there's no problem.
It might be a bit much to tail a large group like this, but this time, it's different.
If they act as a diversion, she should be able to get even closer to her brother.
With a slight smile, Kaju bows to the three seniors.
"Well then, I'll join you. Thank you for today."
