Three hundred years ago, a divine event destroyed the old world and wiped out most of humanity. The few survivors now live deep underground in sprawling tunnel cities, far from the desolate surface and the lingering threat of the Emissaries, mysterious and hostile remnants from the war between god and mankind. In this post-apocalyptic setting, one such settlement is No. 9 Regeneration City, a place where most residents live quiet, cautious lives, but a desperate few take on a dangerous job.

This story follows nine individuals burdened by hidden pasts and personal secrets. They have been assembled by an unnamed organization and are brought together 50 meters beneath the city in abandoned disposal tunnels. Their task is to work as scavengers, venturing into these hazardous underground spaces to recover anything of value, including relics from the old world, minerals, or anything that can be sold for a profit. The rules of their employment are brutal. They are divided into three teams of three people each, and their payment is based on what they recover. There is a special bonus if an entire team returns alive, but if a member dies, the cost of recovering the body is deducted from their pay.

The true danger comes from the treacherous environment and the Emissaries of the old world that still lurk in the tunnels. The group must also navigate betrayals and the shifting loyalties among themselves, as each of the nine characters has their own hidden agenda beyond just earning money. Some seek revenge, others search for the truth about the world's destruction, and their individual motivations often lead to conflict or unexpected alliances. The manga explores whether people are capable of real change and carries a subtle thematic undercurrent of anti-colonialism.

Over the course of the series, the scavengers delve deeper into the mysteries of the underground, uncovering the secrets of the old world's destruction and the true nature of the Emissaries. The story was published in four volumes, with the first two released simultaneously in July 2024, followed by a third volume in January 2025. The fourth and final volume was released in August 2025, as the series concluded earlier than originally planned.