When the sun reached its highest point, its shadow disappeared. Criminal police Han Dongxiu (Han Shigui is acted the role of) in order to confirm his conjecture on a murder case that has been settled, resulting in the accidental death of his son, he has since become depressed. Fourteen years later, a homicide case seems to have something to do with that case, when Han Dongxiu once again began to pay attention to the son of a victim, you Han (Gao Xiu). Accidentally know the private investigator who is helping the consortium boss investigate fianc é e Liu Meihao (Sun Yizhen). He learned from the private investigator that the woman named Liu Haomei was Li Jia, the daughter of the murderer who was thought to have committed suicide. The two children Han Dongxiu had suspected at that time are now grown up and are also around him because of the murder. In the process of tracking down Han Dongxiu, he discovered the truth of the murder and the recent murder, while behind the truth is a pair of unrequited lovers who can never meet in broad daylight. The film is adapted from the novel White Night Walk of the same name written by the famous Japanese reasoning novelist Keigo Higano. The novel has been made into a TV series in Japan and has been a great success.