Dear Detective

Ten years ago, a massacre occurred in the orphanage. As a survivor, Ning Sisi was adopted by a criminal investigation psychology professor and his wife. Ten years later, Ning Sisi received a mysterious letter for Ning Sitian on the day she returned to China. In order to find out the truth of the matter, Ning Sisi was involved in a murder case and met Xiao Yihan, the detective who solved the case. Behind the many cases are buried secrets that were unknown ten years ago.