"Year 252 M.C, in this era which plants are almost extinct and the land is barren, a strange disease developed. 'Shinigami's flower,' the unique lethal flower that carries death." The disease is curable if found in the early stages but if left till transformation stage it becomes lethal and the only option left is extermination. These are all dealt with by request to 'Gokurakuen,' the national medical institution specializing in dealing with shinigami's flowers.

Our protagonist, Doctor Ichinose Souma, is the class representative of Mobile Team Unit Class 1. As his class gets too few requests, he and his assistant Hina often get into trouble interfering with other class's jobs.