The unit specializes in the investigation of serial murders and is led by Van der Bijl, a former murder and robbery detective who gained fame for his handling of several high-profile cases. Each episode focuses on a serial killer. The main character, Colonel Piet van der Bijl, also known as Die Byl, is loosely modeled on the famous ex-detective Piet Byleveld.

François van Heerden, a mid-40s Afrikaans family man, has become devoid of any care or concern for his own measure of happiness, and so convinced of his ill-fated existence, that he is wholly unprepared when a chance encounter unravels his clean, controlled life.