The era is modern. The setting is a massive fictional port metropolis without an official city name.

This city is crisscrossed by a next-generation high-speed network called the "Neon Ring Network."

Multiple layers of elevated roads, underground tunnels, long straights along the sea, and complex junctions. Due to its scale, it is a transportation network often called the city's blood vessels.

By day, it is a public road supporting logistics and commuting, but at night, it transforms into an unofficial race track.

Street racers, tuners, and nameless challengers speed across the neon-lit pavement.

There are no clear rules. What decides victory or defeat is speed, skill, and judgment.

Those who seek top speed. Those who close the gap through cornering. Those who choose the optimal route at junctions.

The reasons for running are also varied. Those aiming for the top, those outrunning their past, those confirming something. And some eventually vanish.

The city continues to shine, indifferent to such events.

The city has no official name.

It is a massive port metropolis facing the sea, inhabited by stateless and multinational people, as well as beings who are not human.

Languages and cultures are not unified, and there is no organization that governs the entire city. There is no direct management by a state, nor is there a unified order.

The scale of the city is close to a real-world metropolitan expressway network, but the complexity and density of the high-speed network far exceed it.

In the city at night, there are many non-human existences.

Yokai and beastfolk who came over through smuggling. Cyborgs and enhanced humans modified as payment for debts. Those who lost their lives on these roads and became ghosts. There are even rumors of aliens.

Few know their pasts.

It is not that there are no laws. Vigilante groups exist in various places to crack down on smuggling, robbery, and violent incidents.

However, they do not intervene in competitions between street racers. That is because it is not seen as a crime, but as a part of urban society.

At night, street racers exchange information via the unofficial app [RING://].

The identity of the operator is unknown. It is not even known if they are still active or if they no longer exist.

Posts are short, written in cryptic sentences that do not directly indicate location or time. Those accustomed to it can read the meeting point and time from that alone.

All that is needed to participate is a single reaction. Neither real names nor whether one is human is questioned.

A street racer's only ID is the street name they use.

Race results are not officially recorded. All that remains are the traces of the run and the rumors told by someone.

Posts by those who have vanished are not deleted and remain on [RING://] to this day.

──────

[RING://]

There is no official operator for [RING://].

It is said that someone created it in the past, but their name, face, and status of life or death are unknown.

There is no official way to use it either. Posts are short, and locations and times are not clear.

Even so, those accustomed to the Neon Ring Network can read the necessary information. To the uninitiated, it looks like nothing more than a meaningless string of characters.

Posts are a mix of Japanese, English, and unknown languages. Users naturally see translations like subtitles, but the mechanism for this is also unknown.

No words are needed to declare participation. Simply sending a reaction to a designated post is enough.

No official win-loss records remain on [RING://]. What is saved are the traces of the run and the rumors of those who saw it.

Exactly which PA the racers are gathering at is not accurately displayed either. Only information like "That place seems to be lively" flows through.

Posts by those who vanished midway also remain. Whether they disappeared after a defeat or became a ghost, it is the same.

No one can delete them.

Few people use their real names in this city. Whether one is human is not questioned either.

All a racer needs is a single street name.

[RING://] is different from general SNS. It is a place where even the boundary between the living and the dead becomes blurred.

Even now, short posts are being made somewhere.

"Tonight, at Azure Thunder."

List of Neon Ring Network Areas.

<<Azure Thunder Bayline>>

A long-distance straight along the sea. Machines with excellent top speed have the advantage, but a mistake leads to a large gap.

"Stardust PA"

A parking area around the Azure Thunder Bayline. It has many users and is known as a meeting point for street racers.

<<Black Ring Circular>>

A massive circular area in the city center. There are many curves, and machines with both speed and cornering performance have the advantage.

<<Iron Rust Industria>>

A narrow area passing through the industrial district. Contact with general vehicles or walls is likely to occur, and there are many sharp curves. Machines with a tight turning radius are suitable.

"Iron Sound PA"

A parking area near Iron Rust Industria. Mechanical sounds are constant, and tuners and maintenance personnel gather here.

<<Deep Layer Undergrid>>

A tunnel area beneath the city. Since GPS is unstable, it is necessary to grasp the surroundings by intuition. It is a place where a driver's concentration is tested.

"Fog Light PA"

A parking area within the Deep Layer Undergrid. There are few users, and an eerie atmosphere lingers.

<<Sky Arch Sky-Layer>>

A multi-level area where multiple elevated roads overlap. There are three routes—upper, middle, and lower—and the choice at junctions determines victory or defeat.

"Zenith PA"

A parking area on the topmost level of the Sky Arch Sky-Layer. It offers a panoramic view of the city and is popular not only with street racers but also with tourists.