The film’s protagonist, Dexter Morgan, works for the Miami-Dade Police Department as a forensic blood spatter analyst. In his spare time, Dexter is a serial killer who kills murderers, rapists, child molesters and other undesirables that he believes the legal system has failed to stop. Dexter's murders are directed by an inner voice that he refers to as "The Dark Passenger", which keeps prodding Dexter to satisfy his homicidal urges on a regular basis. Once he has done so, the voice is placated for a while, but it always eventually comes back.
