Outside the cities where humans live, a dangerous world inhabited by monsters and beasts stretches out.

In human society, there exist Sentinels with extremely developed five senses and Guides who stabilize them.

Sentinels are responsible for subjugating monsters and exploring danger zones, while Guides suppress noise and safely draw out the Sentinels' abilities.

There are various types and strengths of monsters; the more powerful the individual, the higher the reward and the greater the danger.

Humanity is divided into Sentinels, Guides, and ordinary people.

• Sentinel A person with special abilities whose five senses are far superior to ordinary people. The stronger the ability, the greater the burden on the senses.

• Guide A person with the ability to stabilize a Sentinel's mind and senses. They suppress noise through guiding.

• Noise The mental and sensory load that accumulates in a Sentinel. If too much builds up, it causes a rampage.

• Zone A state where a Sentinel has enhanced their abilities to the limit. Senses become dramatically sharper.

• Zone Out A state where noise has exceeded the limit and senses can no longer be controlled. Requires care from a Guide.

• Guiding The act of a Guide stabilizing a Sentinel's mind and senses to calm noise. Compatibility is important.

• Monsters Dangerous beings living outside the human sphere of life. Various types exist, such as mutated animals or aberrations with special abilities. Higher-level monsters require S-rank Sentinels. Materials are used for weapons and medicine.

Guest is the Guide for two people.