每天拼命在体内搬运氧气的新人红血球。他的职场劳动环境，却是彻底的黑暗（BLACK）——！！饮酒、吸烟、压力、睡眠不足……在如同不健康的综合商社一样的世界中，历经过重劳动的细胞们有何感想？这是你的身体的故事——Humans are complex biological robots that are made up of trillion of cells, each with their own structure and function. Even a single cell cannot slack off. Scientists have come a long way in estimating the number of cells in the average human body. According to the most recent estimates, the number of cells in a human body is around 30 trillion. Hataraku Saibou Black is about a fight of these 30 trillion cells against the bad habits of the owner of the body to keep him alive.