"The Suspect" is a British detective thriller series about the investigation of a murder. The body of an unknown woman with 21 stab wounds is discovered in an illegally dug grave in a city cemetery. It is revealed that the victim had been visiting the well-known and respected psychologist, Joe O'Laughlin, for a long time. Without much enthusiasm, the doctor agrees to write a character reference for the deceased patient to the police. However, after this seemingly simple procedure, Joe himself becomes the main suspect.