He'll charm fellow officers with a doughnut, wile away a Sunday with his girlfriend Rita, or chop up a victim and package their body parts in plastic bags. Hiding beneath the mundane exterior and contrived facade of Dexter, a charming blood spatter expert for the Miami Police Department, is an obsession with meting his own twisted brand of justice: stalking and murdering the guilty.

Rita's everything Dexter's looking for in a girlfriend: broken and sexually disinterested. Surviving a violent ex-husband and harboring the mental scars to prove it, Rita is struggling to raise two kids on her own. Together, Dexter and Rita attempt to create a sense of normalcy in their often twisted lives.

As Dexter puts it about his cop sister, "if I could have feelings at all, I'd have them for Deb." Her career ambitions - getting out of vice and into homicide - fall short due to insecurity and the belief within the department that she does her best police work in a 'sex suit'. Deb looks up to Dexter but senses there is more to him than meets the eye.

An ill-tempered vet, Doakes is the one cop on the force, supposed experts in judging character, who suspects something isn't quite right with Dexter.

Whether a wink, a sly look or hand on his shoulder, Lt. LaGuerta, the division's boss and resident dictator, makes no attempt to hide her sexual interest in Dexter.

A fellow homicide detective, Batista works closely with Dexter on forensics cases and while he may not share Dexter's blood lust, he definitely appreciates the art of killing.

Harry Morgan, Dexter's adopted father and a former homicide detective, was first to spot Dexter's passion for human vivisection and helped his son channel his homicidal impulses in a more constructive pursuit: delivering vigilante justice.

Masuka is the wise-cracking forensic expert who assists Dexter in crime scene investigations, who's never too busy to make an inappropriate pass at Debra.