Veteran detective So-young and her rookie partner Hyun-gi happen onto an incendiary homicide case. While Hyun-gi is goofing up and distracting So-young, So-young senses that there is something wrong in the case. They discover that the present case is somehow related to the mysterious death of a girl ten years previously. At this point, So-young becomes plagued with nightmares in which the girl appears. And the serial killings continue.