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 (Joo Sang-Wook) is former top-notch detective, but now works as a professor. He then becomes the leader of Special Affairs Team TEN. Nam Ye-Ri (Jo An) has been a detective for 4 years. She joins Special Affairs Team TEN because of her psychological reasoning powers. Baek Do-Sik (Kim Sang-Ho) is 24 year veteran detective. He possesses a keen sense of intuition, which he honed from his many years as a detective. Bae Do-Sik also joins Special Affairs Team TEN. Park Min-Ho (Choi Woo-Sik) is a new detective. He joins Special Affairs Team TEN after impressing Professor Yeo Ji-Hoon with his reasoning powers.