In the series, the 8-year-old male protagonist，Park Su Ha，and Jang Hye Sung who was a high school student at the time, witnessed the scene that Su Ha's father was killed by Min Jun Kook. Jang Hye Sung was threatened by Min Jun Kook, but she still testified in court against his crime. Min Jun Kook threatened to revenge on Su Ha and Hye Sung after being released from prison. Su Ha promised to protect Hye Sung, but the two persons have never seen each other since then. After 10 years, Su Ha finds Hye Sung and takes advantage of his ability of thought reading to help her solve the cases. The two people fall in love with one another....