The human's unhealthy lifestyle choices cause constant chaos within their body, placing numerous cells in precarious situations with germs, bacteria, and foreign substances. Amidst this turmoil, Sekkekkyuu AA2153 and Hakkekkyuu U-1196 struggle to fulfill their duties and mourn those who perish. Hataraku Saibou Black portrays their valiant attempts to sustain bodily health in a vastly different setting. Nevertheless, the human's wellbeing deteriorates, casting doubt on their efforts' effectiveness.