Set in a stratified city where the wealthy discard what the poor depend on, this manga drops its protagonist from the slums into a vast underground disposal zone after he is falsely accused of murder. Inside the Pit, monstrous creatures assembled from compacted waste roam freely, kept in check only by a group of fighters called Cleaners armed with specialized weapons. Driven by grief and the need to clear his name, the main character joins their ranks in a story that uses its striking industrial setting to explore class, survival, and justice.