"No one can stop this rainstorm. When darkness creeps, there will always be someone who keeps moving, and some chooses to wait." One month ago, Van Nadd's doctor Oreno received a letter, informing him that a small town in Melaerka Mountains has been free of plague, probably because of the propagation medium of plague: water source. In a rescue operation of plague patients, Oreno failed, and is regarded by the riotous citizens as the poisoner. Supposed to be executed, he has his identity changed, and involved in a bigger conspiracy...