* * *
Even after school let out, I remained in the classroom, staring intently at my smartphone screen.
I had boldly claimed, "I will solve these Seven Wonders myself," because I wanted to show Konuma-senpai even a little bit of my growth. However, I am not exactly the most academic person, nor am I particularly good at solving riddles.
...Wait, why did I want to show my growth to Konuma-senpai so badly?
...No, no, that is a different mystery altogether, and it does not matter right now.
I take pride in being my Master's disciple and understanding her thoughts to some extent, but even so, I feel like there are too few hints.
I surely won't figure it out just by thinking alone. They say that "idleness is like a poor man's wisdom," or something like that.
Unless I borrow the strength of someone more intelligent...
Just as I was thinking that—
"Tsubame-chan, what's wrong?"
"Natsumi-san...!"
Natsumi Osada-san, the petite honor student who is number one in our class, reached out a helping hand to me. ...Though, being petite myself, I shouldn't really be the one to say that.
"You were groaning 'Uuuuugh' out loud, you know?"
"R-Really...!"
I have shown her an embarrassing side of myself...
"So? Are you worried about something?"
"Natsumi-san, are you by any chance good at solving mysteries?"
"Mysteries!?"
Natsumi-san, who had large eyes, leaned in toward me with those eyes sparkling (pun intended...?).
"Yes, I love them! What kind of mystery is it?"
"To be precise, I do not even know if it is a mystery, but... it is this."
"Uh-huh, uh-huh!"
I showed her the mysterious memo I had received from Konuma-senpai.
* * *
① 3:53
If you throw a five-yen coin into the hole of the bass drum in the Instrument Room from two meters away while crouching and it goes in, the image of your future self will appear there.
② 4:03
In the scenery you see after walking a few steps while looking to the right from a point where only the Administrative Office is visible, a future key person will emerge.
③ 4:22
Immediately after counting the stairs from the library to the first floor one by one, if you climb the same stairs while counting from the first floor, there will be one extra step.
④ 4:44
Of the two anatomical models standing in the corner of the messy Science Lab, if you put a beige cardigan on the older one, something precious will appear.
⑤ 5:17
Among several leftover cans of Calpis Water, one contains a 1% higher concentration than indicated.
⑥ 5:45
※Impossible? From an outdoor table in the empty cafeteria, if you use a hand mirror to reflect the setting sun onto the top of a stack of trays, letters will appear.
⑦ It will only appear to those who have followed the six wonders exactly on time.
* * *
"Hee... So this is... supposed to be the Seven Wonders?"
"It seems to be a riddle disguised as the Seven Wonders. My Mas... a senior I deeply respect made this himself, acted like he found it on the internet, showed it to another senior, and invited them to tour these Seven Wonders."
"I see, so that's a tactic too..."
"A tactic...?"
"Nothing!"
When I tilted my head, Natsumi-san waved her hands in front of her.
"So, um... what is the relationship between Tsubame-chan's respected senior and the senior they toured the Seven Wonders with?"
"R-Relationship...?"
I wonder why she asked. It might be necessary for the mystery, but I honestly do not know how to describe the relationship between those two.
As I struggled to find the words, groaning "Uuuuugh..."
"...Could it be, childhood friends?"
Natsumi-san tilted her head with a glint in her eyes.
"No, no, that is not it."
"I see..."
...Natsumi-san is usually a very smart, lovely, and wonderful person, but for some reason, she always gets a little scary whenever she mentions the phrase 'childhood friend.'
In any case, right now, it is the relationship between Master and Konuma-senpai.
Hmm, I feel like Konuma-senpai denied it once, saying it wasn't quite like that.
"...Best friends, perhaps? Even though they are a woman and a man."
"I see..."
Saying "Hmm, hmm..." Natsumi-san gently tapped the smartphone screen.
"...This senior is quite a playful person, aren't they?"
"Did you figure something out!?"
"Yeah, probably. Mystery number ⑦ is more of a 'question' than a 'mystery.'"
"Is that so!? Please tell me!"
As expected, Natsumi-san was brilliant!
"Ahem... Well then, do you notice that there are several unnatural points in these Seven Wonders?"
"Which parts...?"
I read them over again, but I couldn't figure it out easily.
"First, the wording is unnatural."
"The wording..."
"Yeah. Rooms like the 'Instrument Room' or 'Administrative Office' don't exist in this school, right?"
"Now that you mention it..."
If these were real Seven Wonders, there might be a possibility they were called that in the past, but at this point, it has been established that Master made them.
If so, I can infer that there is some meaning or reason for using those specific words.
"Next, the time display is unnatural."
"The time display...? Um, do you mean the 3:53 or 4:03 parts?"
"Exactly! If these were Seven Wonders that specify a time, shouldn't they be written in the 24-hour format? Otherwise, someone might think it's in the middle of the night... In fact, people would usually assume it's the middle of the night, if it weren't for the mention of the setting sun in number ⑥."
"I suppose so..."
As I made a confused face, Natsumi-san laughed bashfully.
"...Well, that's just hindsight after I realized it, though."
Hindsight...?
"Also, this '※Impossible?' part feels very out of place, so when I tested a theory, it seems like I was right."
"What do you mean...?"
"Following the six mysteries according to the time means, basically..."
Smiling gently at me as I remained lost, Natsumi-san took a notebook out of her bag and opened it.
"If ① is 3:53, then what are the 3rd and 53rd characters of that sentence?"
"The 3rd character is 'Raku' (Fun). The 53rd character is, um..."
I counted fifty-three characters, one by one.
"...Is it 'Hou' (Release/After)?"
"Probably. In that case, I'll write it here."
In her notebook, Natsumi-san wrote:
* * *
① Fun / After
* * *
"Um, Natsumi-san, sorry to ask something unrelated, but what is that notebook...?"
"Don't worry about it!"
Natsumi-san gave a bright smile, but I could see through the back of the page she was currently on. It was covered in a terrifying amount of text, making it quite difficult not to worry about it...
And on the title part that was bleeding through the paper, it looked like it said: 'Thorough Discussion! ~Does the bond of childhood friends last forever?~'
"Tsubame-chan?"
"Y-Yes...!"
"Let's count the others!"
Faced with that pure, innocent smile, I swallowed my questions for the time being.
And so, we counted them one by one and wrote down each character.
...Then, what emerged there was—
"Master, this is...!"
* * *
① Fun / After
② (shi) / school
③ (ka) / later
④ (tsu) / Da
⑤ (ta) / t
⑥ (?) / e
* * *
"...The purpose of the senior who made this was simply the act of touring the Seven Wonders together."
Natsumi-san wore a faint, bittersweet smile.
"Is that so..."
...What did Master want to do with this? Did she want him to notice? Or did she want it to remain unnoticed?
"Uuuuugh..."
"Ahaha, Tsubame-chan, your face looks even more troubled now than before it was solved."
"The mystery only deepens...!"
Natsumi-san accompanied me with a strained smile for a while as I continued to frown.
* * *
"Azuma."
After parting ways with Taira-chan, my brain craved some sugar. I ended up buying a can of Calpis and was walking back toward the classroom while drinking it when—
"Oh, as expected of the former student on duty. You've got something good there."
The President of the Calpis Club was walking toward me from the opposite direction.
"You're overestimating the student on duty. Anyway, about the Seven Wonders."
"Seven Wonders? What about them?"
She shrugged her shoulders in an exaggeratedly feigned manner, even though she knew exactly what I was talking about.
"I heard it from Taira-chan. She said she didn't actually hear them from someone else."
"What's with that complex phrasing? That's hilarious."
"It's not hilarious... Why did you do something so elaborate?"
"Ahaha, I was bored, you know? Since I retired from the club."
Azuma admitted easily that she was the one who made it, without me even having to press her.
"What kind of reason is that... I mean, if you were bored, you could have just asked me normally."
"If I invited you by saying 'Let's wander around the school pointlessly,' would you have come with me?"
"That's..."
I'm not sure about that, but...
"Well, it's only natural for Konuma to complain. Sorry for making you waste your precious after-school time on something meaningless."
"No, that's not what I wanted to say..."
"Ahaha, thanks for being considerate. Well then."
Saying that, Azuma gave a light bow without looking at my face and tried to walk away.
...It wasn't that I wanted to make things feel so gloomy.
I just wanted to 'compare notes' with Azuma.
"...It was fun."
When I muttered that to her back, Azuma turned around, her eyes wavering.
"Konuma, could it be..."
"...It wasn't a date, though."
I told Azuma while making my best fed-up face with my poor acting skills.
Then, after her large eyes sparkled, Azuma—
"Konuma, what are you talking about? When did I ever say it was a 'date'?"
She flashed an exceptionally mischievous and happy smile.
"No, Azuma, because that code...!"
"Code? I wonder what you're talking about?"
"Wow, I fell for it...!"
Azuma grinned once more, said "Ahaha, see ya," turned forward, and headed toward the shop in high spirits.
"I see. Even a certain someone who is way too dense can solve it if it's a code, huh..."
I muttered that realization, which likely won't be of any use in the future.