This is a story that may or may not have happened in a certain fragment of a certain layer. This is one of the several cafes on the university campus. Renko and Merry quite like this one. It's got a trendy ambiance, and they often have new cakes on the menu. Despite being on the same campus, every cafe here is unique. This one is Merry's favorite kind. It's an outdoor cafe without the cons of an outdoor cafe. The power of science keeps it safe from the rain and wind. It's a typical all-weather construction. There used to be a time when people avoided sidewalk cafes unless it was a clear and sunny day. But that's a thing of the past. These all-weather constructions use a sunroof that lets the sunlight in but keeps the rain and wind out. They're like a barrier. Then again, any building or plot of land acts as a kind of barrier. That's why vampires can't enter buildings unless they're invited and why it feels like a challenge to enter a university when you're not a part of it.

Renko Usami is a member of the occult circle known as the Secret Sealing Club. She goes by the name Renko. You don't want to talk to her about physics. You'll regret it. (M.H.) Maribel Hearn is a member of the occult circle known as the Secret Sealing Club. She goes by the name Merry. She's pretty knowledgeable. It's rare to come across someone who's willing to talk to me about physics these days. (R.U.)

Renko and Merry were born in the age when the world's population had to be regulated. Capitalism inevitably led to a decline in population. But that happened faster in Japan. This country has achieved a period of stability now that the population is at its lowest. At one point, people feared it would fall to zero. A country can't exist without people, and so the government took measures to stop that from happening. You might assume that this population decline would occur nationwide. However, since most of the population was concentrated in urban areas, that is where the extreme measures were enforced. Eventually, there was a sharp population decline in these areas, but the infrastructure was kept in perfect condition to ensure the growth of a new era. An optimized civilization comes to life when the population stays small. Every person was now more significant. Even the resources allocated to each person increased. This, in turn, raised the standard of living. However, although every person had more living space, energy, supplies, and time, they were generally required to perform tasks that would have been assigned to multiple people in the previous era. Some feel that such a society is formed depending on the kind of abilities people have. Urban areas are currently facing a new population-related crisis. To meet the increasing demand for space per capita, cities and telecommunication need constant development now more than ever before.

Renko Usami majors in super-unified physics. Strong force, electromagnetic force, weak force, and gravity were the four fundamental forces of the universe, but it has now been proven that these are different aspects of the same force. This was one of the ultimate goals of theoretical physics, and with its discovery, humanity is now capable of unraveling everything about the universe… at least on paper. That is why this branch of science that evolved in many stages, starting with Newtonian Mechanics, has been crowned "super-unified physics." However, it is still in its infancy as an academic discipline, as the unification of the four forces happened only recently. Unfortunately, this development has made physics more theoretical than ever. No matter how much progress is seen in theoretical physics, proving the new theories through experiments and observations is hardly possible. That's because the amount of energy required to perform those experiments increases exponentially. Trying to figure out the limits of the universe is not an easy task. The deeper you dig, the darker it gets. Even if procuring an immense amount of energy was possible, safely managing it would be close to impossible. Thus, research becomes important. But who knows how long it'll take to prove any of it? That's why super-unified physics proceeds without proofs, just like natural philosophy from before Newton's era.

The discovery of new barriers is seen as super-unified physics revealing more aspects of the world. It is an odd interpretation. Changes in science shouldn't affect the way the world is. Maybe there was a fifth force at play here. There was a scholar who insisted on this theory. However, it had taken lots of effort to come up with the unification of the four forces, and she wasn't allowed to contest it. Everything had to be explained using the four forces. Nothing exists outside of these forces. And if something couldn't be explained, it was merely the fault of the scientist. Times had changed, but the rigid mentality hadn't. That's exactly why Renko Usami was immensely intrigued by Maribel Hearn. Super-unified physics, which was only a philosophical world in Renko's head, became something that could be proven or refuted through experiments and observations. The answers to the mysteries of the universe resided in Merry's eyes. At least, that's how Renko saw it.