The group of police is investigating criminal cases that happened in the city. The team consists of 12 members of police which is Lee Sangyeon, Bae Joonyoung, Kim Younghoon, Lee Jaehyun, Lee Juyeon, Moon Hyungseo, Choi Chanhee, Ji Changmin, Ju Haknyeon, Kim Sunwoo, Son Youngjae, and Heo Hyunjoon. They do a lot of research together but their investigation is unsuccessful because they cannot catch the killer. The leader of the police, Lee Sangyeon said that the cases are unexpectedly the same in pattern. Will the polices able to catch the killer before more victims killed?