Hong Kong tycoon Song Zhentao is shot and killed, and psychologist Ye Baoyan becomes the sole eyewitness. To prevent the witness from meeting with an accident, Song Zhentao's eldest son, Song Zhihao, hires bodyguard Zhou Ying to protect Ye Baoyan. In the process of getting along between Zhou Ying and Ye Baoyan, the two go from mutual suspicion to risking their lives to protect each other. As the truth of the shooting incident gradually unfolds, Zhou Ying's true identity will also become the biggest barrier between him and Ye Baoyan.