The blazing morning sun promises another triple-digit day, and inside Stage 16 at Sunset Gower Studios, things already have heated up.

The blazing morning sun promises another triple-digit day, and inside Stage 16 at Sunset Gower Studios, things already have heated up.

Michael C. Hall still hasn't broken a sweat, though, as he moves with steely quickness in a pivotal scene for Showtime's Dexter, in which he plays a blood analysis expert for Miami's finest who spends his off-hours offing bad guys.

At the moment, Dexter Morgan is carefully manipulating blood samples.

Then he pauses.

With no dialogue, the day's call sheet reveals Dexter's voice-over in which he's torn but resolved about framing an innocent man to cover his own misdeeds, even if it goes against a tenet of his father's: Never hurt the innocent.

But there's also the No. 1 rule, the voice-over continues: Don't get caught.

Wouldn't want that to happen -- considering there's a city rife with cold-blooded killers ripe for execution.

Dexter, which returns Sunday, is one of those dark, complex cable dramas with a tragic, yet appealing antihero -- the sociopath we love to root for.

The days of 'Magnum, P.I.' are gone, says executive producer Clyde Phillips. Part of what we love in our antiheroes now is that shadow side, that part of what we love in ourselves because we all have that shadow.

As the second season opens, it's some 38 days after Dexter saves the city, and foster sister Debra Morgan (Jennifer Carpenter), by murdering his only brother, the notorious Ice Truck Killer.

For all that was resolved (last season), there are some really open wounds for Dexter, says Hall in his trailer during a break as he fusses with the laces on his sneakers. I mean Dexter, on all fronts, has people closing in on him.

What with Sgt. Doakes (Erik King) stalking him around every corner, even leading Dexter's ally, Lt. Maria LaGuerta (Lauren Velez), to believe that Dex may have something to hide. And his girlfriend, Rita Bennett (Julie Benz), suspects him of framing her ex-husband and sending him to prison.

The noose tightens even more when evidence of Dexter's killing sprees surface, bringing FBI serial-killer hunter Frank Lundy (Keith Carradine), out on the prowl. He's teaming with Dexter's own comrades on the force, Angel Batista (David Zayas), Vincent Masuka (C.S. Lee) and Debra.

Now Dexter finds himself unable to relax or kill.

I cant believe how stressful this guy's life is, Hall says, and he can't talk about it with anybody.

Except with those closest to him -- the viewers.

I'll tell you, if you couldn't hear his internal dialogue I think it would be a very different story, Velez says of Hall's haunting voice-overs, which offer glimpses into the mind of this madman. That's the genius of the show.

It premiered with a positive critical push and became the highest-rated drama on the channel, according to Showtime President Robert Greenblatt, and he gave the show an early second-season greenlight after only five episodes.

I hesitate to use the word because it can signify something that is dull or boring, says Carradine, an admitted fan, but this show appeals on a more intellectual level, but it's a viscerally entertaining show.

Carpenter offers: It's kind of like Showtime serving up this really stiff drink and every once in a while they are going to throw it in your face, but you'll still keep coming back. It's intoxicating.

And sometimes perplexing.

One of the great things about Dexter is that he means something different to different people, says co-executive producer Daniel Cerone of the character based on the Jeff Lindsay novels.

You can talk to one fan of the show and they connect with this guy's insatiable need to kill, Cerone continues. Then you talk to another fan who thinks Dexter's a good guy killing bad guys. It can be confusing but it's accessible to people because they can bring their own moral center to the show.

The thing that the show aims to explore, says executive producer John Goldwyn, are the absolutes: Am I absolutely evil or am I absolutely good? The answers lie in Dexter's relationship with his foster father, former cop Harry Morgan (James Remar, who's seen in flashbacks).

Therein lies the eternal conflict, Goldwyn says. Did Harry make him the way he is, or was he born the way he is? Is it nature or is it nurture?