Park Soo-ha (played by Lee Jong-suk) is a high school boy who can read other people's minds. He got this ability at the age of 9 after he saw his father's death in a car crash. The crash was caused on purpose by the character Min Joon-guk (played by Jung Woong-in). Jang Hye-sung, (played by Lee Bo-young) an 18-year-old high school girl, was a witness of the murder and testified in court. The killer had warned her not to testify. Min Joon-guk is sent to prison. He tells Jang Hye-sung that as soon as he gets out of jail, she will be killed.