This drama is about a professor who has genius mind and a special crime detective police woman try to solve a chain of murder case. They both know eachother since they were little but for some reason professor lost part of memory . His father was the police psychology doctor. His father was appointed to take the truth out from the most dangerous psychopath of all time and the when detective was little her father was a prison guard for that psychopath. However that psyopath escape from prison through creating big scandal. That psychopath kidnapped that prison guard and after that he killed that psychological doctor and then disappeared, after long when they become adults they determined to catch that psychopath. Through the investigation they found this chain murder cases exactly like the murder cases happened in past then they identified that psychopath isn't dead. There are few people close these two. But the psycopath hiding as a their close friend. Who will be the psychopath? Will they catch him or will he kill them?