Defense specialization and puzzle-solving.

If Maple and Sally have entered the game now, their destination is only one place—the Guild Home in the Eighth Layer.

The field stretches endlessly with water. The Town consists of buildings rising above the surface, connected by hanging bridges. With flying machines available, shortcuts are effortless. Convenience is not poor.

The Guild Home is located within one of these structures—the 【Maple Tree】. When Maple and Sally enter, Kanade waits inside, having just solved another puzzle crafted by Izu.

“Hey, you two. I’ve been waiting.”

“Another puzzle-solving day, huh!”

“Let’s do our best—though my main role is combat, really.”

It is certain that combat is what is expected of the two, in the sense that Kanade cannot handle what she cannot do.

“Fufu, you two have fought enough… how about trying a different dungeon here?”

“A different dungeon… what kind?”

“Puzzle-solving only. There are weak monsters, but no boss. The goal is reaching the treasure at the deepest part of the ruins.”

“Huh, Kanade, you’ve already solved those puzzles?”

“No. I knew you’d come. That’s why I left this one.”

Kanade had seen the information about a rare dungeon focused solely on puzzles, with no boss. She could have cleared it herself, but chose to leave it behind. This underwater ruin exploration was precisely the kind of challenge she believed Maple and Sally would want to experience.

“Then we can all think and try together!”

“Can you beat Kanade’s speed?”

“Try your best. Fufu, you might just win one question.”

“For now, let’s try a two-on-one, Maple.”

“Yes, that’s right.”

“The oxygen levels are quite tight. We’ll have to work hard to solve the puzzles.”

“Yes, ma’am!”

“Alright. Let’s do our best.”

The two had memorized the cipher symbols thoroughly. They were ready to begin.

They had prepared equipment to extend their dive time. The three had maximized their available activity time. They set their destination to the ruins deep beneath the water. They left the Town.

After some time traveling, the trio reached the roof of a spire rising from the water’s surface. A large hole opened in the roof. Peering through, they saw a staircase descending through transparent water below.

“Maple, Maple, look outside for a moment. It’s enormous.”

“Really? Let me see!”

Sally’s voice directed them not into the spire’s interior, but outward, toward the surface. There, dozens of meters away, stretching far down into the depths, a vast underwater ruin came into view.

...Puh! Incredibly large! Can we keep breathing long enough?

That depends on our pace with solving puzzles. And avoiding being interrupted too often by weak monsters.

Leave that to me!

And you, too. I’m counting on both of you to solve the riddles.

I’ll do my best!

Just to confirm... we can’t cut through shortcuts, right?

Apparently it’s designed to be impossible.

Understood. Then we’ll have to go straight ahead, properly.

When you’re ready, let’s go. No need to worry too much. We still have the final option—[Cradle of the Earth].

Ah, right! That’s true.

Maple rarely uses it in daily life... it’s strong, but we can manage without it.

Oxygen recovery through burrowing into the ground has already been confirmed at the eighth layer. As long as we remember to watch for skill seals, the final safety net is properly in place.

A willingness to solve puzzles is evident. Maple and the others step forward into the water, having donned their diving suits.

Swimming toward the stairs visible from the spire's roof, they find a spiral staircase descending directly below, which they follow in a continuous turn.

"Wait?"

"An immediate dead end... but there were no letters, were there?"

A stone wall blocks their path. The spiral staircase continues ahead, yet a partition cuts it off mid-way.

Scanning the surrounding walls, no cipher-like markings appear.

Faced with an abrupt standstill, the two examine their surroundings more closely, searching for any clue.

"Definitely more difficult than the dungeons we've cleared."

"I'll check this wall—something might be there."

"Then I'll take the opposite side."

"I'll inspect the stairs and ceiling."

Fortunately, no monsters have appeared yet. Maple studies the wall carefully, examining it for any irregularity.

— Hmm... Wait...?

Maple, staring intently at the wall, notices a cluster of aquatic plants growing on it. Among the scattered, irregular growth, one strand extends longer than the rest, forming a single line. At its tip, the plant clearly traces a small circle.

— Hey, hey! Isn’t that suspicious?

Maple points, and the others look.

— Yeah, that looks right.

— Could it be a button? She’s the discoverer, and she’d be sturdy enough to withstand a trap. Should we have Maple press it?

— Yes!

Maple swims up to the ceiling, then presses the center of the circular formation made by the plants firmly.

As Maple had predicted, the section sank slightly, becoming a button. The partition blocking their path slowly retracted into the side walls, revealing the continuation of the spiral staircase.

"Got it!"

"Looks like the right answer. Nice catch, Maple!"

"Good start. The road ahead is long, but let's keep going like this."

"Ooh!"

Having smoothly overcome the first puzzle, the three descended further into the tower.

On the way down, they effortlessly eliminated a small school of fish that appeared only as a token presence, reaffirming that this was a puzzle-focused dungeon. They now felt certain there would be no issues with combat.

When they finally reached the bottom of the tower and opened the iron door, they found themselves in a corridor split into two branches. The first thing that caught their eyes was the encrypted script carved into the wall ahead.

"Ah! Both of you—there are characters here!"

"Really. If there are, let's read them first... um?"

"Hmm... I see."

The characters arrived directly, just as in Japanese kana, and both finished deciphering the text. Yet the passage read as a meaningless sequence of letters.

"Wait...? Hey, hey, Sally, maybe we made a mistake?"

"No, something's off. Right? Kanade."

"Yeah. Even when read straightforwardly, it makes no sense. Is there a clue somewhere? Maybe we need to shift a few characters, or substitute them... something like that."

"Hmm."

"A clue... maybe it's hidden in the background, like before... ah!"

"Sally?... Ah!"

Maple notices that her gaze follows Sally’s. She had not seen it before—the cipher had drawn her attention immediately upon opening the iron door. But now, turning back, she sees small characters etched onto the door itself.

“Got it! Um… ‘Three steps back, observe the battlefield’?”

“Let’s take it literally. Shift the letters three places as instructed. Sally and I will try opposite directions. If our interpretation is correct, one of us must be right.”

“Understood!”

They re-examine the text. This time, the cipher resolves into a coherent sentence.

“‘To the left, only remains of death’.”

“So…!”

“Hmph. Looks like the correct answer is to the right.”

“Kanade, you knew, didn’t you?”

“Really!? You noticed the hint too?”

Sally says this, and Kanade hesitates. A faint, uncertain smile forms on her lips. Then she begins to speak.

The answer was known, but the hint went unnoticed. Really, isn’t that right?

“Huh? H-how…?”

“Hmm. The moment I see the letters, some of them shift in my head without warning. So even without a hint, I can figure it out.”

“I see… well, I suppose that’s expected from Kanade.”

It is hard to believe, yet Kanade’s past record makes it clear this is no lie. Just as Sally’s evasion is beyond ordinary, so too is Kanade’s ability to process information—unthinkable for anyone else.

“Wow! Seriously? So if you said ‘shift five letters,’ you’d know?”

“‘Puzu wipi zebi yate yugo o e hifu guwa.’”

“Whoa.”

“Um… um… Wait—yes! Correct! Wow! You’re amazing, Kanade.”

The speed of the incantation seemed impossible to misunderstand. Repeating it slowly, the two confirm it together. Shift five letters—exactly as expected—and decryption succeeds perfectly.

“Yeah. I’ll leave the brainwork for 【Maple】 from now on.”

Maple’s innocent reaction and Sally’s open astonishment make Kanade chuckle softly.

“...ahaha, hehe. Yeah, that’s how it is. My method’s a bit of a cheat, so I’d rather not use it. We’ve got three of us, after all. I want to solve it step by step, searching for clues properly. That’ll be more fun for both of you, right?”

“Yeah. Thanks for thinking of us. Then I’ll only ask you when I’m truly stuck. I’m sure you’d answer if I cried.”

“Alright, I’ll solve it before Kanade this time!”

“Yeah. But… maybe I’ll need a bit of a handicap?”

Fufu... It's fine. Try solving it before me, both of you. I'll gradually increase the handicap.

The ruins are long. There might be a moment somewhere where we can catch up?

Come on! Let's try our best!

The three set another goal besides reaching the farthest point, and swam forward along the right path as they had deciphered.