Chen Mo, a freelance writer with mild social phobia, moved into an old apartment in search of peace and quiet, but was troubled by the cry of a girl coming from the vacant room downstairs at midnight.
As he investigates further, he is horrified to discover that the cry is a "time echo" from an unsolved case ten years ago. From a passive listener, he gradually turned into an "eavesdropper" and "case solver" across time and space. With the help of a retired detective, he gradually revealed the truth that the girl was murdered in cold blood by her biological parents. Finally, through an incredible method, he left evidence in the "past" that pointed to the "present", brought the criminal to justice, and also saved his soul.
