Showtime's new "Huff" is not your ordinary series -- not by a long shot. A bad choice of words, perhaps, because in the opening episode, it is a teenage patient's fatal gunshot to the head that throws psychiatrist Craig Huffstodt's life into turmoil.

Deeply unsettled by the tragedy that occurred in his office, the compassionate doctor, played by Hank Azaria, is forced to confront issues in his own life. But the physician finds that it's not so easy to heal himself.

"Huff," in the words of creator Bob Lowry, is "the only existential comedy-drama on television."

Lowry said that "Huff" springs from a perception that he developed through the ups and downs of his own life, which includes work as an actor, a corporate speechwriter and a television producer.

"I'm 55," he said, "and I've been rich and I've been poor and I've had work and I've been out of work. And somewhere along the way, I came to the belief that people don't wake up until they face death."

Not necessarily their own mortality, but as in the case of Huff, death in front of their own eyes.

A drama with humor, some of it fairly dark, "Huff" opens with a relatively long, evocative and highly creative introductory sequence along the lines of HBO's "Six Feet Under," "Sopranos" and "Deadwood." A tribute to the art of editing and an indulgence that premium channels such as Showtime can afford, the sequence offers an innovation: The (barely discernable) dialogue in the intro will change slightly each week, incorporating bits from prior episodes. The title music is by W.G. "Snuffy" Walden, Emmy-winner for the music for NBC's "The West Wing."

Although the early episodes lay the groundwork for the series, Azaria said the show gets even better.

"I like the early episodes, but about halfway through, we sort of hit a stride of very, very intriguing stories," he said. "The characters seem to start jelling, getting new insights. It starts getting very exciting, very outrageous."

Azaria is surrounded by a sterling cast in "Huff," including several Tony Award winners.

One of them is elegant Blythe Danner as his manipulative mother, Izzy, who lives in an apartment over Huff's garage. Paget Brewster is Huff's strong-willed wife, Beth. Anton Yelchin, 15, son of championship figure skaters Victor and Irina Yelchin, is Huff and Beth's thoughtful son, Byrd, a character Lowry said he wrote to be "fragile and frail but not weak."

Oliver Platt plays Huff's buddy Russell Tupper, a somewhat crass lawyer whose pithy one-liners often serve as reality checks for Huff. Russell's initial assurance that Huff has no legal liability regarding the suicide is comforting, but doesn't assuage Huff's feelings of guilt and failure over the boy's death.

Russell, however, has problems of his own -- and appears unrepentant about them. In the second episode he has an encounter with a prostitute; in the third, he has a drug party with the people who are installing his new plasma television.

And it turns out that he may be wrong about Huff's legal situation.

Executive producer Lowry, who plainly likes the character of Russell, said: "I have so many places to take him -- he has so much work to do. . . . He's really been hurt."

Also in the cast are Jack Laufer as a homeless Hungarian who may be real or may be a fantasy, but who nevertheless forces Huff to face his feelings (and reassures him that "you're a good person"); Kimberly Brooks as Huff's secretary, Paula Dellahouse; and Andy Comeau as Huff's schizophrenic brother, Teddy, who lives in a locked facility. Each episode begins with Huff talking with a patient and ends with a visit to Teddy, who listens to his brother the psychiatrist unburden himself.

Robert Forster is scheduled to appear briefly as Huff's estranged father ("He's dead to me," says Izzy), and Swoosie Kurtz is Beth's mother, who has cancer and refuses chemotherapy.

The 13-episode first season features several notable guests, including Lara Flynn Boyle, who plays

a jailed manic-depressive in the second episode; Annie Potts as the angry, guilt-ridden mother of the suicide patient; Bob Saget as a self-absorbed, drug-addicted actor; and Tony winners Stephen Spinella and Faith Prince (Spinella plays a lawyer, and Prince shows up in four of the season's last episodes).

"Huff" comes not only with big names in the cast, but also with the enthusiastic backing of Robert Greenblatt, a former Fox Broadcasting executive who became Showtime's entertainment president a year ago. "Huff" is one of several new offerings that signal a change in Showtime's programming since Greenblatt's arrival. In a move unprecedented in television, Greenblatt gave the series the greenlight for a second full season four months before the first episode ever aired. Lowry said the renewal came even before he had told Greenblatt the plotlines for the last three episodes of the first season.

Greenblatt decided to hold "Huff's" premiere until after the World Series. But when Azaria was offered the theater role of Lancelot in Mike Nichols's "Monty Python's Spamalot," the executive decided not to delay giving "Huff" a second season.

"It was as good as any show that we had ever had, and none of us had seen a scenario where we would not renew it, so we thought, why not do it now?"

Azaria finished taping the first season of "Huff" in early September, then in mid-October began rehearsals for "Spamalot," which will open in Chicago on Dec. 21. That musical will move to Broadway in February. He plans to appear in the show until June, do the second season of "Huff" in the summer, and rejoin "Spamalot" in the fall.

He said he looks forward to switching back and forth: "I really enjoy the idea of doing this ['Spamalot'] for six and eight months and then going back and doing the more nuanced character of Huff."

With its dark humor and a pilot focused around a suicide, "Huff" was difficult to pitch to television executives, Lowry said. The show didn't fit into the current mode of series that lend themselves to franchise spinoffs, such as Dick Wolf's "Law & Order" and Anthony Zuiker's "CSI."

Greenblatt, then running the Greenblatt Janollari Studio with David Janollari, was interested, but was too busy producing shows such as HBO's "Six Feet Under"; UPN's "Eve," "One on One" and "Platinum"; and Gregory Nava's "American Family" for PBS.

Still, Greenblatt knew "Huff" could be a good series. "We were in the middle of doing 'Six Feet Under' at the time, and it really reminded me of that writing, that voice -- the dysfunctional family, the job the Huff character has that brings unusual people into his life," Greenblatt said.

At Fox, Greenblatt spent eight years developing shows such as "Ally McBeal," "The X-Files," "Melrose Place" and "King of the Hill." He also supervised pilots for "Dawson's Creek," which went to the WB, and for David Chase's "The Sopranos," which became a runaway success on HBO.

Greenblatt couldn't get "The Sopranos" on Fox because it was too unconventional and too ground-breaking for the broadcast network to air.

"We were trying to push the envelope at Fox, but we couldn't push it that far. It was a big regret that I had to give it away," he said. "The same thing for 'Six Feet Under.' Again, fortune smiled upon HBO and they kind of made it one of their own."

By the time Greenblatt arrived at Showtime -- where he could avoid some of the censorship and decision-making problems that plague broadcast networks -- he found that "Huff" was already a go.

"It was one of those serendipitous things," he said. "The Showtime executives fell in love with it the way we did, and they bought it."

Greenblatt, 44, who is in charge of entertainment acquisitions and programming, is overseeing Showtime's focus away from original movies and toward the kind of series that have made HBO the Emmys leader. Showtime has approximately half the number of households as HBO, half as many subscribers and half the revenue.

"I'm trying to find a handful of things that are really original, unlike anything else on television," he said. "The focus for us is on scripted comedies and dramas, which Showtime has been light on in the past."

But he's high on one series that will be largely improv, Kirstie Alley's "Fat Actress." Guests already signed include John Travolta, Kid Rock and Carmen Electric.

"It's an unconventional kind of show," he said.

Just what he wants.

HUFF

Sundays at 10 p.m. on Showtime