Synopsis: Han Seung Min (Yoon Kye Sang) is a popular professor at the Police Academy who became the star of global criminal psychology with a dissertation he wrote at the age of 20. However, after an unexpected confession of murder, he goes to jail. There he meets his ex-lover, criminal profiler Yoo Hee (Go Ah Sung). Yoo Hee loses her father to the murder, and she is conducting interviews with the murderer. The drama focuses on the process of the two putting the pieces together, like a puzzle.