The story revolves around a talented hacker who decides to enroll in Police University alongside his girlfriend. For the past twenty years, Yu Dong-man has been a successful investigator in various law enforcement departments, specializing in theft and murder cases as well as combating cybercrime. Now, he has become a teacher at Police University. Among his students, he immediately takes notice of two individuals: former hacker Kang Sung-ho and his beloved Oh Kang-hee.