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Ryoichi was so obsessed with absorbing relevant knowledge from his first friend here that he forgot to take a close glance of the atmosphere around. After leaving the jar, he just followed S without knowing where they were heading to. They walked on a smooth plane where it was translucent with some seashells as decoration. Looking from this kind of "floor" to upward, the color faded gradually from semi-transparent to transparent, so the sunlight could shine through the ceiling, if there was any ceiling there. There was no corner between the "floor" and the "wall", but rounded, which showed that they were kinda in a ball-like building.

As for walking, indeed they were walking by having the toe touch the floor, but the way was more like spacewalk, except for a lower height of jumping.

Ryoichi followed S to the edge of the wall. Above there was a sign "Exit", but no door or no shape of a door was ever revealed. He was about to ask S, who went straight to it and just passed through the membrane-like wall, immersed himself to the blue water outside.

Ryoichi screwed up his courage and mimicked his companion. He easily succeeded but then started to sink.

S, instead, was steadily floating suspending in water.

"S!" Ryoichi cried for help.

"R!" S rushed to him to support from the armpit and laughed, "haha, use your legs, you dumb."

Getting close to S got him a change to observe this nice person. Orange hair, blue eye, and baby face. Most importantly, Ryoichi realized that the silver-grey color was not the skin, but a suit of very thin clothes, or membrane to be more previous. He looked down to himself and found out he also wore such clothes as well. Meanwhile, not sure it was the clothes or born with, there were webs between fingers, very small parts and transparent so that hard to notice, but should be very useful when swimming.

So he started to imitating S to paddle his limbs, 'just like swimming' he thought, and then quickly acquired the skill and stopped sinking. However, seemed like he could not move very fast yet, so S slowly accompanied him to tour.

Back to the previous life, Ryoichi had never got time for vacation. Neither swimming nor diving had he ever experienced, due to the lack of time, money, and of course his little interest. He, however, only watched the ocean via TV program. The current condition under water, as he could see, was much crowded and tense than he could remember.

The place where they just came out, he would say hospital, was indeed a huge oval bubble membrane as he observed inside. The ceiling was too transparent to be defined the edge, but seemed to be 20 feet under the sea level. Underneath the building was a pillar extending to the abyssal sea. Paralleled to the hospital, thousands of similar pillars were standing with different space between. Each pillar had a similar oval building on top, while there were also ellipsoids, or you could say "bubbles", attached to the body of the pillar. The deeper the pillar went, the more crowded the ellipsoids were on with deeper color.

Among them all, there was a biggest one not far from here, larger than any other including the hospital. The basic shape was also a huge oval "bubble" laying on a giant pillar, but between the main building and the pillar, there also stretched out several huge floating objects, gently swinging like pedals, which made the overall appearance a sunflower with a huge pearl on. Meanwhile, the closer to this giant pillar, there were less pillars around.

"That is the palace." S explained to me. "You see the periphery outside the palace? That's where we are working everyday. Only elites can get into the palace. I'm kinda curious what looks like inside."

He also said that those bubbles were the buildings for living. People with higher class would live in closer to both the palace and the sea level, where there would be also many facilities, such as the hospital, court, academy, entertainment, etc. As for those number people, they would live in the ellipsoids in deeper sea. Sometimes, there might be several people squeezing in one small bubble.

S and R swam to the opposite of the palace for a while and arrived the destination.

"I think you might be hungry. Well, to be host, I'm really starving, so let's have some food."

They entered a smaller bubble sphere than the hospital. It looks like a pub. Now, they could step on the floor again, which made Ryoichi feel easier than swimming.

S went straight to the owner, a strong man who had a type of water plant clamped between his teeth.

"Two jelly, one is tuna, the other is," he then asked R, "what flavor do you like?"

"Ummm, I don't know."

"I like tuna. There are also eel, salmon, silverfish… It's okay if you want only plant."

Ryoichi thought he might start with the normal ones. "I'll have eel please."

In a moment, the owner gave them two round stuff, which looked like jellyfish but with no tentacles. Inside was some paste, one was yellow and the other one side was black.

S held the yellow one up and put his mouth closer to the top of it. There seemed to be a suction nozzle where S started to suck up the things inside the jellyfish.

Ryoichi would like to do the same to his own food, but he didn't know how to eat it with the helmet on, so he asked S for help.

S requested the seller for a very thin straw and stuck one side to the jellyfish, while putting the other side through the helmet worn by Ryoichi.

"Oh, that's very interesting, so the helmet won't be broken." He sucked one bite, and it indeed had, as he anticipated, a smell of fish, but it didn't cause him any nausea. Instead, he felt it fresh and a little sweet. "What's in it?"

"Oh, just the regular fish and some healthy plant."

"Why is this straw so thin?"

"That's the mouth of garfish. You remember that? The fish with mouth like a needle."

After finishing half, Ryoichi asked: "I'm curious. Why did you, I mean we, start living under water? What happened to the land? How can we breathe under water without any device? Since when has we begun building the ocean world?"

"Okay, okay." S waved his left hand to me, "I know you lost your memory and has a loooot of questions, but I can promise to answer all of them. After all, I'm not very good at history you know. I'll only try my best. Alright, so as I know, we started to explore the ocean very early because there are plenty of resources, which was when people had to wear some equipment or take some transportation to dive in the sea. As the climate is gradually changing over decades, our ancestors have never stopped finding another place to live. I remembered they even tried to explore the outer space, but unfortunately, none of the exploration ever found somewhere humans could live. Because of the warming, sea level was rising and gradually encroaching land area, so people started to think of building base on the ocean."

"Okay, that makes sense. So, are you suggesting that all of this living depends on technology, right? Is it the suit we wear can help us breathe under water?"

"Yes but not exactly. The helmet you're wearing, yes, it's the product of technology, but the breathing thing, no. We're, how to put it, reformed to accommodate the living under water."

It drove Ryoichi's confusion, "How?"

"Very long time ago, it's said that a scientist found a mermaid and did some human body experiment, combining the respiratory system of mermaid and human, and made a person can breathe under water like a fish. After years of evolution, this is it. We, including you, are just like a fish with human's shape, or you can say, we're mermaids with two legs."

What he said really startled Ryoichi, "so I can too? I mean, I don't need the helmet."

"Well, I suggest you wearing it for now. The reason that helmet exists is that it can prevent some bacteria. In some seasons, people will get allergic to the specific bacteria, and the helmet can protect us."

'Like the old face mask during COVID-20, when everyone was required to wear it.' Ryoichi thought.

"Alright, so one more question. That has puzzled me since the beginning."

"Sure, go ahead."

"How can we talk in the water? That's unscientific."

S shrugged and said: "I don't know, bro."