He is introduced as a serial killer and a blood spatter analyst for the Miami Metro Police Department. As Dexter is the title character, he is featured in every episode.
Dexter has an adoptive sister by the name of Debra Morgan and later learns that he has a biological brother by the name of Brian Moser. His adoptive parents are Harry and Doris Morgan, both of whom have passed away prior to the pilot episode.
The first season of Dexter is an adaptation of Jeff Lindsay's first novel in the Dexter series, Darkly Dreaming Dexter. Subsequent seasons have featured original storylines.
This season aired from 1 October 2006 to 17 December 2006, and follows Dexter's investigation of "The Ice Truck Killer."
At the start of the series, Dexter Morgan has settled into a steady life of ritualistic killing doubled with his life as a forensics blood spatter analyst. He is seen by his colleagues as a lab geek and only one man, Sgt. James Doakes, suspects him of being anything other than this.
In order to fit in with society, Dexter maintains amiable, superficial relationships, which he calls "blending in." No one is aware that he relentlessly hunts murderers to satisfy his deep-seated need to kill.
It’s night time in Miami, and Dexter is focused on his next kill, Mike Donovan, a choir conductor and pedophile who murdered three young boys. After a choir performance, when Donovan enters his car, Dexter (who is hiding in the backseat) pulls a garrote wire around his neck. He orders Donovan to drive to the location where Dexter recently dug up the rotting corpses of the dead boys.
Dexter drags Donovan inside a pump station and forces him to look at the bodies of the boys. Donovan pleads for his life but doesn’t deny that he killed them. In tears, he says that he couldn’t help himself. Although Dexter is a killer, he never hurts children and Donovan thoroughly disgusts him. Dexter injects Donovan with M99 and he immediately collapses. Dexter secures Donovan, wrapped in plastic, to a kill table. As part of his kill ritual, Dexter collects a blood slide through a scalpel cut on his victim’s cheek. After he notifies Donovan of his fate, Dexter cuts into his neck with a reciprocating saw. Later, Donovan’s remains are dumped off the coast from Dexter’s boat, Slice of Life.
When Dexter returns to his apartment, he is called to a crime scene at the Seven Seas Motel by Vice Officer Debra Morgan, his adoptive sister. One of his co-workers, Vince Masuka, is surprised to see Dexter there because there is no blood anywhere. The dismembered bloodless body intrigues Dexter and he admires the skills of the perp. Debra is soon assigned to the homicide dept. to work on the case which grows increasingly complex.
Dexter returns to work, bringing donuts for his co-workers, and obtains a file for a potential victim from Camilla Figg in Records. Sgt. James Doakes approaches Dexter and demands a blood report on the Cokehead Murders Case in which a man and woman were killed during a drug deal. Before Dexter writes the report, he takes off to examine the crime scene. The blood evidence tells Dexter that it was a crime of passion, not a drug deal gone wrong. Later, at a briefing, Dexter tells Doakes and Lt. Maria LaGuerta of his findings. He explains that the male victim was quickly stabbed in an artery, but the killer took his time with the woman, slashing her multiple times. Dexter suggests that it’s probably a boyfriend and this is proven true.
As part of his cover as an average guy, Dexter dates Rita Bennett, an attractive mother of two (Astor and Cody) whose abusive husband is in jail. Dexter feels that Rita is perfect for him because she is not interested in sex and he can keep her at a distance. Dexter believes that if they become intimate, she will feel his emotional dysfunctions, and he doesn't want to blow their relationship.
Dexter begins to stalk Jamie Jaworski, a rapist and murderer, who works as a parking valet. While on the job, Jaworski noticed a woman named Jane Saunders, whom he kidnapped and killed in a snuff film. During his trial, Jaworski escaped justice due to a faulty search warrant. However, Dexter doesn’t care about warrants and he breaks into Jaworski’s house while he’s at work and confirms his guilt.
On the night of his death, Jaworski is trespassing on a construction site to steal copper piping. Dexter surprises him with a photo of Jane and injects him with M99. He restrains Jaworski to a stack of sheet rock and wraps him in plastic. When Jaworski awakes, Dexter collects a blood slide and confronts him about Jane’s murder. After Jaworski admits he did it, but shows no remorse, Dexter decapitates him with a cleaver. While he is dismembering Jaworski, Dexter receives a phone call from Rita, asking to see him.
On his way to Rita’s house, Dexter is followed by a refrigerated truck. After it passes him, Dexter follows it to a closed bridge, where the driver makes a U-turn. The unknown truck driver flashes his high beams, and tosses a human head out of the window. It smacks against the windshield of Dexter's car, as the truck takes off. The police are called to the scene and Dexter is questioned about what happened. After a stop at Rita’s, he eventually makes it home only to find a a dismembered doll inside his freezer. Dexter is eager to play this game.
The truck is soon found with a large block of ice inside, holding the fingertips of a victim, with the nails painted in different colors. The murderer is dubbed The Ice Truck Killer. The events surrounding the Ice Truck Killer Investigation begin to lead Dexter deep into his past.
Dexter’s next target is Matt Chambers, a repeat drunk driver who caused multiple accidents. He always escaped conviction due to his skill at faking emotions and fabricating stories. Unfortunately for him, Chambers ends up on Dexter’s kill table inside a vacant liquor store.
Jeremy Downs is a a young man responsible for the death of another boy when he was fifteen. After Jeremy is released, Dexter almost kills him until Jeremy says that he only killed his victim because he was raped. Dexter decides to let him go but later finds out that Jeremy killed again. Before Jeremy is captured by Dexter, Jeremy is arrested. Dexter visits Jeremy in jail and, shortly thereafter, Jeremy commits suicide.
Dexter shows that he may not be quite as distant from humanity as he believes when he spares a life. Dexter is lured to a closed hospital by The Ice Truck Killer where he finds a man, Tony Tucci, partially dismembered, but still alive. Tucci is set up on a kill table with a set of knives nearby, and Dexter is to kill him. However, since Tucci doesn’t fit the Code of Harry, Dexter realizes it would be wrong and anonymously calls the police.
Not long after, Debra begins to date Tucci’s prosthetist, Rudy Cooper.
The Castillos are a husband and wife team behind the murders of undocumented immigrants. At first, Dexter believes that only the husband is responsible, but he later discovers that the wife is in on the scheme. One night, Dexter captures both of them at their Auto Salvage Yard and kills them inside a travel trailer. Since Dexter has limited time, he only dismembers Jorge, and must dump Valerie’s body still whole into the sea. The next day, Dexter is shocked to find Valerie’s body back inside the trailer, having been returned by The Ice Truck Killer.
During the Ice Truck Killer Case, a man named Neil Perry attempts to bring fame upon himself by claiming to be the Ice Truck Killer, only to be proven that he is an impostor. However, it’s found that Perry did dismember his own mother (postmortem) and bury her in his yard.
After discovering that three women shot themselves while undergoing therapy with Dr. Emmett Meridian, Dexter schedules a few sessions with him. Meridian uses a technique to totally relax Dexter causing him to remember a brief image of a boy in blood. Feeling terror, Dexter abruptly leaves the session. Afterward, Dexter lets go of his self-control and finally has sex with Rita. Despite his concerns, Rita remains unaware of his true nature.
During his last session, Dexter tells Meridian that he is a serial killer and then carries out a Kill Ritual in his office.
Dexter is notified that his biological father, Joe Driscoll has died, with Dexter inheriting his house. Although Dexter is skeptical that Driscoll is his father, he and Rita leave to sort out the house and sell it. While there, Debra and boyfriend Rudy show up to help. At the morgue, Dexter takes samples of both himself and Joe and sends them to Vince Masuka to perform a DNA test. Dexter is astonished when it is a match. Dexter suspects that Joe's heart attack was actually murder. However, the body is cremated before Dexter can obtain proof. Later, Rudy is shown at the door of an elderly neighbor. She lets him inside, only to be killed because she saw him at Driscoll’s house near his time of death.
The Ice Truck Killer stages a bloodbath in Room 103 of the Marina View Hotel with the blood from his victims. When Dexter enters the blood-soaked room, he suddenly experiences flashbacks of himself as a small child in the Shipping Yard Massacre. Experiencing a panic attack, Dexter collapses into the blood. Unable to continue examining the scene, Dexter hurries out of the hotel. Later, Dexter returns to Room 103 by himself and remembers seeing the gruesome murders in his past.
Meanwhile, Rita’s soon-to-be ex-husband, Paul Bennett, is released from prison on parole. Bennett is good to their children, and he repeatedly — but unsuccessfully — attempts to reconcile with Rita. After Bennett threatens Dexter, Dexter knocks him out with a frying pan, takes him to his motel room, and makes it appear as if Bennett violated his parole by using heroin. Back in prison, Bennett insists to Rita that Dexter set him up and to look for his missing shoe, but Rita ignores him.
Rudy proposes to Debra and then kidnaps her. To her disbelief, he reveals that he is The Ice Truck Killer and never loved her. During the search for Debra, the police become aware that Rudy Cooper is an alias for Brian Moser.
Dexter follows clues that lead him to a house that he recognizes, and memories come flooding back. He remembers his mother and an older brother playing with him as a very young child. Standing on the porch is Rudy. Staring at him, Dexter calls him “Biney,” his childhood name for his forgotten brother, Brian.
They go inside and Brian tries to reconnect with his brother. Brian tells Dexter about the Shipping Yard Massacre, saying they witnessed it together. He shows some resentment that Dexter was adopted into a good home, while he grew up in a mental institution. At first, Dexter looks forward to a life with his brother (also a serial killer) until Brian takes him to Debra. She is unconscious and bound to a table. Brian insists that they kill her together to sever Dexter’s ties to her. Dexter hesitates, unable to kill Debra, which angers Brian. Dexter is forced to struggle with Brian to stop him from stabbing her. Moments later, the police arrive, but Brian escapes.
Dexter decides he must kill Brian for the safety of his sister. After he lures Brian to his apartment, Dexter incapacitates him, takes him to Brian's residence, and secures him. After a brief conversation, Dexter cuts Brian’s throat and drains his blood. The next day, the police assume Brian committed suicide, and discover the freezer where he cut up his victims and kept their blood.
Everyone, including Debra, remains unaware that Dexter and Brian are brothers. Dexter feels some regret for killing his brother who accepted him, in order to save Debra who would reject him if she knew the truth.
- Mike Donovan
- Jamie Jaworski
- Matt Chambers
- Jorge Castillo
- Valerie Castillo
- Emmett Meridian
- Brian Moser
Victims in Flashbacks
- Jaworski's Dog
- Jeremy Downs
- Joshua (flashback, prevented by Harry)
- Tony Tucci
- Rita's Neighbor (crossed his mind to kill her)
- Tony Tucci
- Paul Bennett (set up to be arrested)
- Debra Morgan
Killed by Others
- Davey Sanchez (by Juan Ryness) (flashback)
- Rudy Cooper (plumber) (by Brian Moser)
- Ice Truck Killer Victims 1 and 2 (by Brian Moser)
- Pool Victim (by Brian Moser)
- Fountain Victim (by Brian Moser)
- Sheri Taylor (by Brian Moser)
- Alexander Pryce (by Matt Chambers)
- Joe Driscoll (by Brian Moser)
- Irma Holt (by Brian Moser)
- Monique (by Brian Moser)
- Fred (by Brian Moser)
- Ricky Simmons (by Norberto Cervantes)
- Kara Simmons (by Norberto Cervantes)
- Norberto Cervantes (by Jail Guard Assassin)
- Season One
- Blood Slide Boxes
- Ice Truck Killer Case
- Angel Batista
- Astor Bennett
- Camilla Figg
- Code of Harry
- Cody Bennett
- Debra Morgan
- Dexter Morgan
- Doris Morgan
- Dr. Pittman
- Esmée Pascal
- Harry Morgan
- James Doakes
- Kill Tools
- Knife Vendor
- Maria LaGuerta
- Mindy Taylor (flashback)
- Neil Perry
- Refrigerated Truck
- Rita Bennett
- Simon (flashback)
- Thomas Matthews
- Vince Masuka
- Angel of Mercy Hospital
- Auto Salvage Yard
- Bayside Elementary School
- Brian Moser's Residence
- Calle Ocho (kidnapping site)
- Crab Festival
- Dade County Courthouse
- Debra's Apartments
- Dexter's Apartment
- Flamingo Park
- Harry Morgan's House
- Hobie Beach
- James Doakes' Apartment
- Joe Driscoll's House
- Juan's Hot Dogs
- Kill Room
- Laura Moser's House
- Loco's Crab Shack
- MacArthur Causeway
- Marina View Hotel
- McCaffrey Pumpkin Patch
- Miami Blades Ice Hockey Stadium
- Miami Metro Homicide
- Miami Motor Court
- Neil Perry's Mobile Home
- Office Park
- Old Port Bridge
- Petrie Beach
- Pink Motel (Miami)
- Precious Blood Catholic Church
- Rita Bennett's House
- Rudy's Yacht
- Santa's Cottage
- Seven Seas Motel
- Shipping Yard
- Shipping Yard Massacre
- Slice of Life
- The Fountain
- The Gazebo Restaurant
- The Salsa Room
- Z Hotel
- "Popping Cherry"
- "Let's Give the Boy a Hand"
- "Love American Style"
- "Return to Sender"
- "Circle of Friends"
- "Shrink Wrap"
- "Father Knows Best"
- "Seeing Red"
- "Truth Be Told"
- "Born Free"
The show's first season received generally favorable reviews from critics. The pilot episode attracted more than a million viewers, giving the channel its highest ratings in nearly two years. 
- Mitovich, Matt. Short Cuts: "Dexter Slays the Ratings, and More" TV Guide, Retrieved 2009-01-16. http://www.tvguide.com/news/short-cuts-dexter-15508/