Jin’s prediction turned out to be wrong.
Specifically, it was regarding Rubina.
Between the excitement and the time difference, she had been awake far longer than usual, and she eventually lost her battle with the sandman. While chatting with Jin and the others, she began to doze off.
"Oh, she really is still a child, isn't she?"
Susanne smiled as she gently lifted the girl and carried her to the guest room Jin had prepared.
"Are you all right, Shu?" Jin asked, checking on the boy, who was the next youngest after Rubina.
"Yes. To be honest, I'm starting to feel a bit sleepy myself," Shu admitted.
When Jin looked at Natalia, she confessed, "Actually, me too..."
Trihart didn't say anything, but he also had a weary look about him.
"In that case, let's call it a night," Jin declared.
＊ ＊ ＊
The next day, at 5:00 AM, Jin woke up earlier than usual.
He had a feeling Rubina would be awake early, and his hunch was spot on. Having gone to bed so early the night before, both Rubina and Shu were already up. Natalia, Trihart, and Susanne followed suit shortly after.
"Haha, looks like everyone had the same idea."
"It seems so."
Even Trihart and Susanne shared a wry smile at Jin's observation.
＊ ＊ ＊
After breakfast, the group traveled to Tatsumi Bay in a Golem automobile.
"Maybe an automobile race next? No... cars aren't common enough yet," Jin mused to himself. "I'd hate to cause an accident. And where there's racing, there are bound to be accidents..."
It was a difficult dilemma, and he arrived at Tatsumi Bay without finding an answer. Jin cleared his mind and focused on the task at hand.
"All right, everyone. This is the Shachi."
"Wow..."
The vessel featured a streamlined hull that looked nothing like a conventional boat. Painted in black and matte silver-white, it was modeled after the orcas—the killer whales—of Earth.
"Come on, everyone, get on board."
Jin led the way, followed by Reiko and Edgar.
"Edgar, I’m counting on you again."
"Yes, Jin-sama. Please leave it to me."
"So Edgar really was a pilot," Shu remarked, sounding impressed as he watched the golem settle naturally into the pilot's seat.
"Sorry for the trouble, Hope," Jin called out to the golem seeing them off at the pier.
"Please, don't give it a thought. Edgar-senpai, be careful out there."
With that final exchange, the entire group finished boarding. The Shachi started its engines and immediately began to submerge.
"Oh...!"
Everyone was instantly captivated by the underwater vista visible through the windows.
"We've only just started the dive," Jin said with a chuckle.
"But it's my first time!" Rubina shot back, her eyes wide.
The Shachi continued its steady descent into the depths.
"How are we actually diving?" Natalia asked.
"When we're moving, we can trim the fins to generate downforce, but for this trip, we're using a gravity control device. By making the bottom of the hull heavier, we can make the vessel's overall specific gravity slightly higher than that of the seawater."
Jin added that because the weight was concentrated at the bottom, the ship was also exceptionally stable.
"Jin-sama, how are you handling the oxygen inside the cabin?" Shu asked.
"In short, I'm using the magi-craft 'Extraction' to separate the oxygen from the carbon dioxide in the air."
"I see! That’s very interesting."
The Shachi had already reached a depth of about ten meters.
"Ah! What's that?" Rubina cried out, pointing at a glowing shape outside the window.
"Those are the Mermaid unit. Since this is an underwater tour, they're following us with lights to illuminate the way."
Once they reached a certain depth, the sunlight wouldn't reach them and the sea would turn pitch black. While Reiko and Edgar would have no trouble, Jin and the guests wouldn't be able to see a thing. To avoid that, ten Mermaid golems were acting as an escort.
"Oh, I see... Ah, a fish!"
Rubina was practically bouncing with excitement as she watched fish dart away, startled by the light.
"We're getting close to the seabed now."
Tatsumi Bay was quite deep, but since they were still relatively close to the shore, the depth was only about twenty meters.
"Oh, what a beautiful fish."
"Are those plants?...Ah, that must be the seaweed."
"That's right. That frilly stuff is wakame-modoki. It's delicious in miso soup."
"Really?"
"The stuff over there is tengusa-modoki; you use that to make agar."
"I love anmitsu!" Rubina chirped.
"The one with the tiny leaves is hondawara-modoki. It's used as an ingredient for seaweed salt."
"Fascinating."
"And that long, giant one is kombu-modoki. We dry it out to make dashi or boil it to eat."
"There are so many different kinds."
The underwater excursion was clearly a success. The Shachi pushed on toward deeper waters.
"The color of the water is getting much darker," Susanne noted.
"That's why we have the Mermaid unit."
"Oh, look! There's a funny-looking creature!"
An arthropod resembling a Japanese spider crab was scuttling along the bottom. It had twelve legs. It was a species even Jin hadn't seen before.
"It is called a 'Dars Crab,'" Reiko explained.
Jin suspected his 400-year-old self had named it after a "dozen"—meaning twelve—pencils. I probably just got lazy and couldn't think of anything better, he thought to himself.
"Ah, look at that huge shell!"
"That is a Shakogai-modoki," Reiko said.
Jin winced at the name. Since it looked like a giant clam—a shakogai—it was just "giant clam-copy."
I definitely just gave up on naming things back then, Jin thought, accurately guessing his predecessor's thought process.
"There are also mineral deposits on the seabed," Reiko continued, guiding the guests through the sights.
Everyone seemed thoroughly satisfied with the underwater stroll, and seeing their joy, Jin felt a deep sense of satisfaction as well.