[Blue Archive] I am the Trinity Checkpoint Chief – Chapter 18

Any student who knows about the Ship of Theseus can be considered quite studious.

It’s not about whether the concept is difficult. It’s simply that not many students are aware of it.

If, every time your ship sustains damage, you replace the damaged planks, and eventually, not a single plank from the original ship remains, can it truly be called the same ship?

“The Ship of Theseus paradox is pretty famous even at Millennium Science School. There’s even a community dedicated to debating it.”

“That’s surprising, but yes, definitely. It was shocking enough to remind me of the paradox.”

“According to my facial expression analysis program, senpai, you’re feeling more bewildered than surprised!”

Toyomi tried to show off her expertise again. Listening to her endless explanations in a state of panic is too much, even for someone as patient as me.

Thankfully, a single glare laced with a hint of menace was enough to make Toyomi clam up. She’s quick to catch on.

So, why bring up a paradox that’s hard to grasp under normal circumstances? Well, it’s because Hifumi-chan’s appearance has changed drastically.

“…Is that really it?”

“I don’t know. As long as it’s not ugly, it’s fine. Ritsuko-chan seems to like it, so it should be okay.”

The truck’s body, once a deep olive green, now sports a pale, Millennium Science School-esque color. At a glance, its length has increased by about 30-40%, and with an extra wheel added to the side, it’s now an 8×4 drivetrain, suggesting they even changed the axle.

The thickly layered armor plates form a rectangular body with plenty of curves. The howitzer, which resembled a turret, has been safely tucked inside a proper turret.

Since this is the Engineering Club, there’s no way they didn’t put effort into the turret. This means aiming is now far easier than before, when it felt like turning a leaky gas valve.

At first glance, it looks like it could be Trinity General Academy’s checkpoint’s ultimate weapon, a nightmare for Gehenna. That’s half true, but there’s a problem.

A huge problem.

“…Uh, the gun looks a bit off?”

“Oh, yeah. The barrel wasn’t that long before. They must’ve increased the caliber length.”

“No, that’s not it. Sigh, no matter how you look at it, that’s not a howitzer caliber. Toyomi, did you maybe bump it up to 5 inches?”

Toyomi didn’t respond. When I turned to look, she was sweating buckets, her answer dripping away with it. Alright, so they definitely increased the caliber. The question is how much.

Even if the Engineering Club is full of tech-obsessed maniacs, they should have some common sense. It’s not like they’d go for something absurd like 7 inches. What was the caliber of Millennium’s artillery team again? It’s been so long since we last talked, I can’t remember. I do recall them scoffing at us for using inches, though.

Now that I think about it, that pisses me off. Who was it that lost a satellite because of an inch calculation error, and why did they take it out on us? The artillery team leader was nice enough, thankfully, or I would’ve been tempted to use my rifle’s buttstock if they’d pushed any further.

No, no, wait. Let’s push that anger to the back of my mind and deal with it later. A diligent student tackles the task at hand first.

Back to reality.

I turned to Toyomi. She flinched again, still silent. I glanced at the other two members. Nekozuka gave an awkward “ahaha” laugh, and Shiraishi-senpai averted her gaze.

This isn’t good. I might need to downgrade my earlier assessment of the Engineering Club. They may be tech-obsessed maniacs with some common sense, but it seems they lack it when it comes to mechanical engineering.

The root of the problem was commissioning them without clear requirements. They use millimeters, so if they scaled things up arbitrarily instead of sticking to inches, that’s a big issue.

Trinity General Academy’s arsenal produces only 4.1-inch shells, and most of the shells sold at Kazeyama are inch-based. If they expanded the caliber to, say, 17cm? Forget Kazeyama’s Trinity branch—we’d have to scour the black market or the Engineering Club’s clubroom for ammo.

In short, we’re screwed.

So, we need to know the caliber to either protest or breathe a sigh of relief. Why can’t they just say it?

“Well, uh… you seem angry.”

“My facial expression analysis program has classified senpai’s expression as pure rage…!”

“…”

Oh.

I thought they were scared of complaints about the commission, but it turns out the client herself was the problem. I think my face is pretty gentle, but apparently, others don’t see it that way. According to Sayuri, when I’m a bit mad, some kind of aura radiates from me.

The club members’ reactions half-prove Sayuri’s theory. I should pin a medal on her later.

I took a step toward Toyomi. She felt a force of F in my direction.

I took two more steps. She felt a force of 2F in my direction.

Haha, damn it. I guess I’ll have to leave the Hifumi-chan issue to Sayuri-san.

Alright, I’ve calmed down. No, I haven’t.

The information Sayuri-san gathered from talking with the club members is driving me nuts. Forget the 4.1-inch howitzer turning into a 6.1-inch long-range gun—how is the chassis holding up over 40 tons?

The frame was designed for 15 tons, and they slapped on an extra 25 tons. There’s no way that doesn’t cause issues. What, did the Engineering Club swap the material for titanium or something?

“Oh, that’s because, during the process of disassembling and reassembling the chassis, we melted down the frame entirely, added some minerals to create an alloy, and improved its durability by…”

“Toyomi, quiet.”

“Yes, ma’am.”

Ugh, she listens so well.

Anyway, including the frame, which was apparently modified as described, how much has changed? I didn’t bring up the Ship of Theseus for nothing. When these kids say they’ll modify something, they don’t just talk—they replace everything they can.

That’s not necessarily a bad thing. Modifications are physical. Yes, a physical reform. Not a risky monetary reform or a land reform that could sway public sentiment.

Modification is a revolutionary, physical reform. No matter how different it looks from before, it only moves forward, never regressing.

For students who might not get that, let me put it simply: It’s better. It’s not bad. The only issue is that it might confuse me for a while.

Anyway, we’ve completed nearly all the tests possible in the Engineering Club’s clubroom.

Basic operation, movement, and tests for the numerous additional functions—though, out of consideration for Trinity students unfamiliar with new tech, they only added about a quarter of what they wanted—were all conducted, and I observed them.

I had some doubts about the engine output, which powers the turret, autoloader, fire control system, rangefinder, and all sorts of electronics while achieving a simulated speed of over 75 mph. I also protested why they made a compartment on the side of the chassis for hiding liquor bottles.

But I wasn’t disappointed. No, I was more than satisfied. I’m practically grateful. For a request from a Trinity student, with whom they don’t exactly get along, they put in this much effort. And they slashed the purchase cost, which would’ve been 300 million yen per unit, down to 10 million yen. There’s nothing not to be thankful for.

“So, yeah. Thank you. You’ve practically rolled out the red carpet for a backwater Trinity girl.”

“Haha, saying it like that makes me a bit shy.”

“We’re the ones thankful to Yamatsu-senpai. We nearly burned through our budget developing a railgun for a space battleship, but your request got us supplementary funding. Thanks to that, we don’t have to worry about food or utility bills for the rest of the term.”

Wait, that means not 100% of the supplementary budget went into Hifumi-chan’s modifications. That’s embezzlement, Nekozuka-chan. If you get caught skimming supplementary funds, it’s not just a slap on the wrist—your head’s on the line. Bold move.

Sayuri-san looked at me. Her expression screamed, Should we snitch to the seminar? I shook my head, and her gaze shifted to the Engineering Club members. She was genuinely considering ratting them out. This, coming from Sayuri-san, who thinks she’s a model citizen because she hasn’t been caught stealing cocoa.

They say anything the clubroom tests couldn’t verify can be tested externally after delivery. Any issues found during the one-week trial period will be fixed for free.

Wow, what a generous contract. Usually, Gehenna kids would set something like this up to scam you, but since it’s the Engineering Club, I trust them. They’re more interested in machine development than swindling money anyway.

I signed the delivery confirmation, and Shiraishi-senpai followed suit. From now on, Hifumi-chan is mine again. I can fire it toward Gehenna to my heart’s content.

After that, we did what people usually do at final meetings. We hugged, promised to meet again. Toyomi and Ritsuko-chan cried, saying they were great friends, and exchanged Momotalk contacts.

Given Ritsuko-chan’s personality, I thought she’d dislike overly explanatory types, so it was surprising she got close to Toyomi. But thinking back, I noticed signs when Ritsuko-chan was all smiles while Toyomi explained things.

Anyway, despite all the chatter and trouble, as the time to part came, my stay at Millennium became a pretty fond memory. I boarded Hifumi-chan Mk.II. The seat felt as comfortable as ever. I started the engine and opened the window.

“Let’s meet again!”

“Contact us in advance next time so we can prepare a proper welcome.”

“Haha, if you say that, I might just show up unannounced!”

Shiraishi-senpai smiled. I gave a knowing smirk. I pressed the accelerator and moved the hulking vehicle toward the back gate.

Screeeech.

Unlike the front of the clubroom, there were no students outside. The exit cut across a sidewalk with no space for a crowd.

I turned the wheel twice and headed toward the Engineering Club’s block. The 2.5x weight increase wasn’t a joke—moving and turning the truck felt noticeably harder than before. Thankfully, the engine noise was quieter, and motion sickness was much reduced.

Millennium’s daytime has surprisingly light vehicle traffic since most students are in class. Of course, that excludes the half-unemployed students protesting in front of the Engineering Club.

I passed the plaza in front of the clubroom. Hundreds of students were swarming toward it. Shiraishi-senpai must’ve opened the main gate. That’s probably a bad call. They’ll be bombarded with complaints and new requests—how are they going to handle it?

If I visit the Engineering Club again, I’ll ask how they dealt with this mess. For now, I just need to figure out how to get home.

“Sayuri-san, Ritsuko-chan. Where should we go to make a grand homecoming that’ll be the talk of the checkpoint?”

“Hmm, wouldn’t it be safer to take the route we came by?”

“How about passing through Abydos High School? I heard something big’s going down there recently.”

Sayuri-san pinched Ritsuko-chan’s cheek for suggesting something unnecessary. But surprisingly, it’s a pretty tempting idea. I forgot the return route anyway, and unlike when we came to Millennium, there’s no navigation installed.

Sounds good, honestly. From what I can see, Hifumi-chan could easily shrug off bullets. If things go south, we can just open the gun ports. The Engineering Club gave us nearly 30 high-explosive shells, so we should have enough ammo for the trip.

Alright, it’s decided.

“Next stop, Abydos!”

“Wait, I told you not to suggest that to senpai… Wait, really?”

“Yup. Through Abydos, I’m gonna see a desert for the first time.”

Sayuri-san freaked out. Ritsuko-chan’s eyes sparkled, her cheeks still stretched.

The desert might scream that we can’t pass, but isn’t overcoming adversity to head toward the Trinity the ultimate romance? I crushed Sayuri-san’s resistance with my checkpoint captain authority. Knowing reality all too well, Sayuri-san sighed and sat back down.

Of course, Sayuri-san, still unconvinced, grumbled and got her cheek pinched by me in an unfortunate turn of events. And we had a mishap where we couldn’t find the route to Abydos High School and had to buy a map.

But it’s time to begin the journey to Abydos—the city of the desert.