During the day, Dexter Morgan is a jovial employee in the Miami Metropolitan Police Department's crime lab, but his meticulously crafted life masks his true nature.
In reality Dexter is a disciplined and murderous psychopath (a self-admitted "monster"), and he slakes his blood lust at night by carefully killing the serial killers he tracks down during the day. Based on the novels (Darkly Dreaming Dexter, Dearly Devoted Dexter and Dexter in the Dark) by Jeff Lindsay.
Dexter is an American television drama series based on the novel Darkly Dreaming Dexter by Jeff Lindsay and adapted for television by Emmy Award-winning screenwriter James Manos, Jr.. Set and produced in Miami, the series centers on Dexter Morgan, a serial killer who works for the Miami Metro Police Department as a blood pattern analyst.

If your like me and find it hard to wait a whole year for a new season to come out, you can fill your void with Jeffrey Lindsay. He has written three books in his Dexter Series. Infact the show was taken from these books so it is cool to see how different they are from each other.

Season 1

Orphaned at the age of three and harboring a traumatic secret, Dexter (Michael C. Hall) was adopted by a Miami police officer named Harry Morgan who recognized his sociopathic tendencies and, instead of getting him professional help, taught him to channel his gruesome passion for killing and dissecting in a "constructive" way: by killing people who "deserve it". His victims, however, include not only heinous criminals (such as mob assassins and serial killers of the innocent), but also less clearly abhorrent characters, such as a young alcoholic responsible for multiple vehicular homicides, and a nurse who poisons patients believing it is to end their pain. Most have slipped through the justice system, though it is not clear any effort was ever made to prosecute either the nurse or Dexter's opening-episode victim, a Catholic choir master who murders children.

To satisfy his interest in blood and to facilitate his own crimes, Dexter works as a blood spatter analyst for the Miami Metro Police Department. Although his drive to kill is unflinching (otherwise overcome by a feeling of "emptiness") Dexter is, through extensive instruction from Harry, able to fake normal emotions and keep up his appearance as a socially-responsible human being. He is well-liked by most of his colleagues (with the exception of Sgt. James Doakes), his girlfriend, Rita (a psychologically damaged rape victim who Dexter uses as "cover" despite his lack of feelings or interest in sex), and her children. The first season focuses mostly on "The Ice Truck Killer" - a serial killer eluding the Miami PD who is communicating with Dexter through his crime scenes. Dexter's sister Debra begins dating Rudy, who is revealed to the audience to be the Ice Truck Killer. At the end of the season Rudy attempts to kill Debra, but is stopped by Dexter. Rudy reveals that he is Dexter's brother. Dexter has no choice but to kill him and make his death look like a suicide.

Doakes doesn't accept the suicide theory and starts tailing Dexter because of his personal suspicions. Rita's ex-husband, set up by Dexter for a felony parole violation, is back in prison proclaiming his innocence, and points Rita to a clue to the truth about Dexter. The season ends with Dexter and his sister entering a crime scene, with Dexter imagining a tickertape parade for himself, complete with confetti and airplane fly-over, and the crowd praising him for his fine work "taking out the garbage". The complete first season of Dexter was released in a four-disc DVD package on August 21, 2007.

Season 2

Dexter begins the season unable to satisfy his urges for over a month due to the constant surveillance of Sgt. Doakes. When the opportunity to kill arises, he has problems executing his victims.

To further complicate matters, treasure hunters discover Dexter's underwater dumping ground for his victims. As the police extract body after body from the ocean, the media dubs the killer the "Bay Harbor Butcher", and FBI Special Agent Lundy (played by Keith Carradine) is brought in to catch the "Butcher".

Rita's relationship with Dexter becomes more tense as she and her children are dealing with the death of her ex-husband Paul, the result of a prison fight. Her late ex-husband's suggestion that Dexter was to blame for his imprisonment eats at her conscience and eventually Rita accuses Dexter of setting up her ex-husband. Dexter admits to setting up Paul, but Rita refuses to believe that Dexter premeditated the crime. She assumes that Dexter is a heroin addict. He acquiesces to being an 'addict', though he characteristically allows the double entendre to go without clarification; in return, she vows to stay with him while he goes through Narcotics Anonymous program. In this way Dexter avoids responsibility for Paul's death (though he set the process in motion) and consequently maintains the rationalization that he only (directly) kills people who are also serial killers. Doakes pursues Dexter until he spots him at an NA meeting, and his first assumption is that Dexter's devious behavior is drug-related.

Deb continues to struggle with the trauma of her experience with the Ice Truck Killer. For a sense of safety and comfort she stays with her brother, another new source of stress in Dexter's life.

Throughout Season 2, the Bay Harbor Butcher (Dexter) is pursued by Lundy, while Deb grows in her affection for the FBI man as well as in her confidence in her detective skills. Doakes returns to pursuing his suspicions about Dexter, and ultimately discovers Dexter's collection of glass slides, containing blood sample souvenirs from all of his victims. The possibility of matching the slides hidden in Dexter's air conditioner with the bodies of the Butcher's victims sets up the climactic process in which Doakes discovers and confronts Dexter (who overpowers him and keeps him locked in a cage, while he sets up Doakes as the Butcher). Only Doakes' former partner, Lieutenant LaGuerta, believes in Doakes' innocence. Her proof of Doakes' innocence is tainted by her efforts to help him, and rejected by Lundy, though he believes she may be right. In the Season finale, Dexter's pyromaniac stalker ex-sponsor/girlfriend Lila serves as the surrogate who blows Doakes into pieces (along with the corpse of another victim Dexter has butchered in front of him), thereby resolving the situation to Dexter's benefit without Dexter having to himself murder the innocent and mostly honorable policeman. Dexter subsequently murders Lila, Doakes' memorial service goes largely unattended, and in the logic of Dexter's world, all is well again.