“From now on… please request it from me when you want to come here. Then you won’t have to get wet…”

“…Ah, yes.”

He was someone who was almost always busy with subjugation and work.

Though she wondered if that would really be possible every time, she answered obediently as there seemed no need to argue about the situation.

They soon entered familiar territory.

A place familiar to both Constantine and Saena in their own ways. The place with the hot spring.

After stopping at a suitable spot, they dismounted.

“This place is really nice, you knew about it already, right Duke?”

“…Have you bathed in the hot spring?”

“Of course! Somehow all the fatigue just melts away, and I feel energized. It’s really great.”

Constantine made a strange expression as he continued his questions.

“Then, today would you like to… take another hot spring bath?”

“Hmm. Not particularly, but I think I need to check something.”

“What do you mean?”

“I found a clue that seems to point to this hot spring. I need to verify it.”

“Hmm.”

Constantine showed a puzzled look, but more than that, he seemed troubled by the fact that she needed to get in the water.

Well, she would have to undress.

Saena felt equally awkward about it.

Even though she wouldn’t be completely n*ked, she couldn’t help feeling conscious of him.

“Then, I’ll… patrol around this area for a while.”

“There might be demonic beasts.” 

He muttered like an excuse.

“What?!”

“No, just in case…”

If demonic beasts had really appeared even rarely, his reaction wouldn’t have been like earlier when she said she had been coming here.

Though it seemed he was just making an excuse because he needed one, Saena understood why he was doing it and simply nodded.

After seeing Constantine move far enough away, Saena removed her riding clothes.

After carefully storing the removed clothes in the luggage bag she had retrieved from him, she took out the translation and read it once more.

“The part I previously translated as ‘hot key’ wasn’t completely wrong.”

Due to the symmetrical grammar, the interpretation order changed slightly. Applying the new structure yielded a similar yet different interpretation.

“Hot flow surrounds the place of the key…”

Though she wasn’t sure exactly what the hot flow meant, since water was typically described as flowing…

Actually, though the water wasn’t completely hot, this was the only place she could think of, so she thought she might as well check.

While she had soaked in it countless times, she had never ventured underwater. Naturally, this sparked a sense of curiosity and anticipation about what might lie beneath the surface.

“Please… let there be something.”

Saena muttered her wish as she stepped into the spring in her undergarments. Though she wasn’t sure why, she had a kind of intuition that if she solved this problem, other things might be resolved as well.

The sensation of warm water enveloping her skin was vivid.

After soaking for a while to adjust, Saena took a deep breath and went underwater.

The spring had a peculiar water quality, appearing both transparent and opaque at once. She had been concerned about opening her eyes in warm water instead of cold, but to her surprise, it was fine.  

Although the visibility wasn’t ideal, the fact that her eyes didn’t sting was a relief. It seemed manageable—she could search methodically, examining one area at a time.

‘The structure is… quite strange?’

But when she actually examined the underwater structure, it was too peculiar to be called a normal spring. This was something she hadn’t noticed when just soaking before.

The shallow parts around the spring’s edges were shaped like large steps, perfect for sitting and soaking.

Because of this, she naturally assumed it had been deliberately designed for hot spring use. However, upon examining its overall shape, it felt somewhat different.  

It wasn’t like there were steps or structured levels. Instead, it gave the impression of the entire ground being hollowed out into a bowl-like shape, then filled with water.

Anyway, it definitely wasn’t a natural spring structure. It felt more like an artificially created pool.

‘…Then isn’t there a higher chance of there being a keyhole?!’

Her expectations rose further.

The smooth floor without any particularly sunken or protruding areas added strength to the hypothesis that it was artificially made.

But that was it.

As more time passed, her thoughts changed.

She had thought if there was a keyhole, it would be in an obviously visible form… but nothing caught her eye. The spring’s bottom was excessively smooth, and the color was consistent.

Had it been a wrong interpretation that there might be a keyhole in here?

‘No, let’s examine it thoroughly anyway.’

Saena surfaced to take in fresh air before diving again.

She drew mental sections from above the spring. It was a feasible method since the spring wasn’t very large. Following these sections as she dove, she began to move forward slowly while feeling the bottom surface with her hands.

As she started feeling the bottom, what seemed to be fine dirt dust that had settled on the surface floated up, making the view murky. Though the light color seemed strange for dirt, that’s what it was anyway.

How many times had she repeated this process?

Saena was coming up for air when she noticed bubbles. At first, she thought they were her own bubbles, but they weren’t.

Bubbles were rising from somewhere at the bottom of the spring at regular intervals.

Unlike the explosively rising bubbles she had seen at the Coldora hot springs before, these bubbles rose small and gentle, pop, pop, just two or three at a time, dissolving before reaching the surface.

They were such faint bubbles that you might only notice them while diving.

‘Where are they coming from?’

Even if faint, the steady rise of bubbles meant there must be some kind of gap. Saena wanted to see this gap and dove again near where she had spotted the bubbles.

As she felt along the bottom, her fingertips caught on something. Her fingers sank into what had appeared to be a flat bottom. When she moved her hand to clear it, the dirt dust that had accumulated in the depression all rose at once, clouding her vision.

Saena closed her eyes and felt the gap with her fingertips instead.

‘…The shape seems… familiar.’

Round on one side and pointed at both ends like an almond…

Could it be a marquise cut shape? Like the black diamond?

‘Could this be… the keyhole?!’

Perhaps due to sudden excitement, her heart started beating wildly. Maybe because of that, her breathing became very rapid.

Saena pushed off the bottom to surface.

“Ah!?”

She was startled by the sensation of someone grabbing her waist. Water splashed everywhere from her violent movement.

“D*mn it! Saya!”

Constantine, who had suddenly appeared in the spring, held her tight and repeated her name.

“Co-Constantine?!”

Why was he suddenly acting like this?

Not to mention, he was shaking violently.

“Why, why are you like this?”

“I was watching from afar… and couldn’t see you…”

“Ah…”

“For quite a while…”

Had she been underwater that long? It seemed he had mistakenly thought she had drowned.

“I was diving.”

Though it sounded strange to say she was diving out of nowhere, it was the truth.

“Were you very surprised?”

Putting herself in his position, Saena thought she would have been startled too. If someone who said they would take a hot spring bath couldn’t be seen, and wasn’t visible anywhere else around.

But this hot spring was actually awkward to drown in.

“It’s not deep enough to worry about.”

Being a small spring, it wasn’t very deep.

“Look.”

The spring water rippled around Saena’s shoulders. For Constantine, it would only come up to his chest.

“I… see.”

“Haven’t you ever gotten in here before?”

She asked, thinking he would have naturally known if he had.

But his answer was unexpected.

“…I’ve never gotten in directly.”

“Directly…?”

Then did that mean he had gotten in indirectly? What did that even mean?

“I’ve thrown Caligo in… no, put him in before.”

“…What? Why would you do that?”

“That bast–no, Caligo really hates it.”

“……”

The way he kept almost cursing suggested his relationship with the Guardian Spirit was quite bad.

More than dislike, it seemed like utter loathing.

“Why does Caligo hate it?”

“This spring contains light attribute particles, which are opposite to him.”

“Ah…”

So this sparkling water quality was because of light attribute particles?

That was fascinating.

But why was there a light attribute hot spring in Kramer territory, which commanded a dark Guardian Spirit? Surely the light attribute hot spring wasn’t here just to torment Caligo.

Was it just a coincidence?

“Then are you okay?”

“Me?”

“Being in here. Doesn’t it affect you?”

“It does give me a headache.”

“What? It hurts?”

Saena grabbed his arm in surprise. She urgently urged him to get out of the water.

“You should have said something if it hurts!”

“No, usually it does, but…”

He stepped up one level toward the shore as she pushed him.

“Right now I’m touching you…”

He stopped mid-sentence. Not just his words, but his entire body seemed to freeze.

“…Th…”

His expression looked about to burst.

As if realizing the contact, Saena felt his arm that she was holding rapidly stiffen in real time.

“S-sorry. In the confusion…”

He hurriedly pulled away. The water rippled with his movement.

But the situation got worse.

Though the contact decreased, the visual stimulation doubled.

Near the shore, the water rippled around their thighs. This meant their thoroughly wet bodies were completely exposed.