The protagonist, having been involved in a bus accident, is reincarnated into another world. Apparently, upon reincarnation, he's given the opportunity to choose a special profession (class). He immediately tries to select a class, but among the top-ranked classes like "Hero" and "Great Sage," he discovers a particularly unusual and mysterious class: "Potionist." While other classes like "Sword Saint" are available, he's utterly bewildered... However, tired of the hustle and bustle of the city, he thinks it would be perfect for a leisurely life, so he chooses "Potionist"—but it turns out to be an incredibly overpowered class!?

Humanity hunted beastly monsters to near extinction, enriching itself while relentlessly expanding into the mountains. But their greed has awakened the mountain's ultimate calamity. Left behind by loss, a lone orphan becomes a ranger, stepping into the wild to keep the fragile peace between mankind and nature, but... (Source: Kodansha, translated)