"Special Affairs Team TEN" is a criminal investigation unit that tackles the most violent crimes in South Korea. These crimes usually have less than a 10% rate for arrests. They chase the most notorious killers who attempt to commit the perfect crimes. Yeo Ji Hoon is a former top-notch detective who now works as a professor. He then becomes the leader of Special Affairs Team TEN. Nam Ye Ri has been a detective for 4 years. She joins Special Affairs Team TEN because of her psychological reasoning powers. Baek Do Sik is a 24-year veteran detective. He possesses a keen sense of intuition, which he honed from his many years as a detective. Park Min Ho is a new detective. He joins Special Affairs Team TEN after impressing Professor Yeo Ji Hoon with his reasoning powers.