It's difficult to explain to someone who has never seen Dexter why it's one of the most riveting and addictive shows on television.
When you try, you tend to sound a tiny bit psychotic.
"It's about this guy named Dexter who works as a blood splatter analyst for the Miami Police Department but is also secretly a serial killer," you say, adding quickly, "except he only kills bad people, the kind the law can't touch.
He has this code of honour and he's played by Michael C.Hall, who is just amazing because he makes Dexter kind of lovable and, well, you just have to watch it."
You finish lamely, and your friend takes a couple steps back.
Fortunately, as Dexter wades deeper into its fourth season, there aren't too many people who haven't seen it, or at least heard of it.
Hall's recent marriage to Jennifer Carpenter, who plays Dexter's foul-mouthed, unlucky-in-love detective sister Debra, prompted a few headlines, and then Hall was nominated for another Emmy.
Now the show has the added mainstream credibility of John Lithgow, beloved star of stage, screen and the children's book/CD circuit.
Lithgow plays the Trinity Killer, a serial murderer as methodical and duplicitous as our man Dexter.
The season opened, in fact, with a woman coming home to find Lithgow, stark naked, heaven help us, in her bathroom.
He later cradled her terror-shaken body in the water and cut her throat, holding up a hand mirror so she could watch herself die.
Chilling and yet perversely beautiful, it promises a most electric season.
When the concept was first floated - a grisly Robin Hood of serial killers - many critics and viewers were understandably sceptical.
But in adapting the novels of Jeff Lindsay, writer James Manos jun created not so much a jolly psychopath as the ultimate outsider.
Darkly hilarious, Dexter is essentially the story of the ultimate misfit - like Sheldon on The Big Bang Theory, Dexter simply does not understand the language of emotion or the social cues that others take for granted.
Guided by his adoptive father, Harry (James Remar), he relies instead on a code of survival, a code that has been tested over the past three seasons by various events, the most important being his growing love for Rita (Julie Benz) and her two children.
After Rita discovered she was pregnant, last season ended with the two getting married.
Many of us spent a lot of time wondering how in the world the writers were going to navigate the murky waters of Serial Killer Dad.
But we needn't have worried - poor old sleep-deprived Dexter has learned to multitask.
What new parent hasn't grappled with the difficulty of juggling family, career and lifelong obsession, be it music, writing, baseball or strapping murderers to a table with plastic wrap and stabbing them to death? Dexter is, of course, dealing with a larger issue - his love for Rita and the kids indicates that he is not so much an Other as he once thought.
He still has to kill, but he discovers that he would rather be revealed than have his family harmed.
Whether such a disclosure comes is up to the writers, although one hopes they would leave it for another season; this one looks to be jam-packed.
Forget "must watch" - this season's Dexter is "can't wait" television.
• Los Angeles Times
Dexter screens on Sundays at 9.30 on the Box (Sky digital channel 5).
