《ZERO DAY》

October 17, 2029.

An infectious disease of unknown origin breaks out simultaneously across the globe.

Initially reported as a virus causing simple high fever and convulsions, the situation completely flips when it is confirmed that bodies begin moving again after cardiac arrest.

The infected continue to move even after death, attacking living humans.

And those attacked become infected as well.

The problem was the speed of infection.

Within the first 72 hours, the medical systems and public security of major cities worldwide collapse simultaneously.

People call this day ZERO DAY.

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Stages of the Infected

Type Ⅰ — Runner

Entities immediately following infection.

Appearance nearly identical to humans

Capable of running fast

Vision and hearing are relatively normal

Tendency to act in packs

The most dangerous early-stage infected

They are the primary reason early cities collapsed so instantly.

Type Ⅱ — Walker

Common zombies that appear as time passes after infection.

Slow movement

Feel almost no pain

React strongly to sound and smell

Move in hordes

Extremely high in number

The typical zombie that people generally imagine.

Type Ⅲ — Hunter

Mutated forms of some long-term infected individuals.

Vision is significantly weakened

Hearing and smell are extremely developed

Active in dark places

Highly sensitive to sound

Much faster than normal zombies

Particularly dangerous in abandoned buildings or underground facilities.

Type Ⅳ — Brute

Extremely rare mutants.

Possess massive physiques due to abnormal muscle and skeletal development.

High defensive power

Easily destroy common obstacles

Often appear at the center of zombie hordes

However, their numbers are very few.

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A Fallen World

Nations have not completely vanished.

The problem is that the state cannot control entire cities.

Therefore, the world is largely divided into five zones.

🔴 Closed Zone

Metropolises with the highest concentration of zombies.

Major cities like Seoul, New York, and Tokyo have effectively become massive infection zones.

Buildings remain, but there are almost no people.

Survivors must risk their lives the moment they enter to scavenge for supplies.

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🟢 Safe Zone

Cities secured by the military and government.

Massive walls have been installed, completely cutting them off from the outside.

Inside, there are:

Residential areas

Hospitals

Power generation facilities

Food storage facilities

Agricultural facilities

Armories

Control centers

Civilization appears to be maintained on the surface.

However, there is a limit to the sustainable population.

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🟡 Frontier Zone

Between the Safe Zones and Closed Zones.

Areas where survivors have settled on their own.

Abandoned schools, villages, gas stations, and factories are renovated and used as bases.

Because government control is weak, it is free but dangerous.

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⚫ Outlaw Zone

Areas where government control has completely vanished.

Places where humans are more dangerous than zombies.

Groups of armed survivors occupy their own territories.

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☣️ Contaminated Zone

Areas with an excessive density of infected.

Even the military prohibits access.

Places where the entire city has effectively become a zombie habitat.

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Survivor Bases

Survivors fortify various locations.

Department Stores

Plentiful supplies remain, and entrances are easy to control.

Large Apartments

Securing high floors makes it easy to block zombie access.

Schools

Wide playgrounds and classrooms can be utilized.

Subway Stations

Underground spaces and connecting tunnels can be used, but they are dark and easy for zombies to hide in.

Mountain Bunkers

Can be completely isolated from the outside, but food and manpower are scarce.

Islands

Relatively safe from mainland zombies, but supply runs are difficult.

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Survivor Society

Civilization has not completely disappeared.

Rather, those who survived have begun to create new rules.

In Safe Zones:

Living quarters may be divided by roles, such as Military → Medical Staff → Technicians → Producers → General Citizens.

Conversely, outside survivors:

Exchange supplies like food, medicine, ammunition, batteries, and fuel.

Money becomes almost meaningless, and practical goods become the currency.

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More Important Than Zombies

The most important thing in this worldview is that civilization has not completely vanished.

In various places, there are still:

Functional power plants

Military bases

Communication facilities

Hospitals

Research labs

Factories

Subways

Ports

Airports

Therefore, survivors do not simply hide to avoid zombies;

They act upon the question:

"Can we reclaim the civilization we lost?"