A Byouma is a medical weapon created by ancient sorcerers to kill the infected or those around the infected and make it look like an illness. Even centuries after the sorcerers have died, these weapons still wander the world, infecting and killing people. Narutaki Soutaro and Izumo Momo are Shadow Doctors, trained to combat these Byouma through unorthodox means. Using magically created anti-Byouma medical equipment, they perform "operations” on the medical weapons to separate them from their hosts and destroy them. Will their special weapons and brilliant teamwork be enough to get rid of all the Byouma in the world?