It’s not often I find myself pondering the duration of an episode of a television series, and whether or not it’s the correct length, but the 30-minute doses in which the story of Showtime’s “Californication” are doled out have always struck me as being just right. With only half an hour to move the narrative along, scenes are generally kept on a tight leash and points are made quickly. There are no dead spots or meandering passages. Instead, each episode is crammed with quips, confrontations, and raunchy high jinks from start to finish.

Weaknesses are also well disguised, if not entirely papered over. For instance, Hank Moody, the hard-living novelist portrayed by David Duchovny, is essentially a sentimental creation who’s narcissistic to the core. If Hank has a dark side, it’s one that’s limited to pastel shades. Compare him, for instance, with the Hollywood writer played by Humphrey Bogart in Nicholas Ray’s film noir masterpiece “In a Lonely Place.” Yes, Bogie’s character was witty and sardonic and, when he wanted to be, passionate and loving — a sentimental Tinseltown portrait of the “writer” as well, if you like. But he was also an alcoholic who made you feel the pain of booze, and he had a pathologically violent side that was downright scary. Moody, on the other hand, is nice to children and a gallant defender of women. The darkest thing about him is his name.

As its title suggests, “Californication,” which begins its second season Sunday at 10 p.m., is both a paean to debauchery and occasionally a critique of it. We’re meant to enjoy Hank’s rebellious instincts — not to mention those of his agent, Charlie (Evan Handler), and Charlie’s wife, Marcy (Pamela Adlon) — and bad-boy antics, and we do. We don’t want these people to behave well. We want them to act like they’re on an expensive cable channel having too much sex, taking too many drugs, and getting into too many mishaps at an hour when children are supposed to be in bed. As far as that goes, they deliver. The show knows exactly what it’s about and I’ve yet to watch an episode that wasn’t entertaining.

The first season of “Californication” ended with Karen (Natascha McElhone), the regally beautiful love of Hank’s life, jumping into his car after dumping her wealthy fiancé, Bill, with whom she’d hoped to live a more orderly, dignified life than the one she had with Hank. The new season begins with Hank and Karen — the picture of boho romance — back together in their house in Venice, along with their Goth daughter Becca (Madeleine Martin).

All would seem to be bliss in the Moody household, if a bit painful at times: Karen has asked Hank to have a vasectomy. This he does in his usual nonchalant style, and of course one of the nurses lets him know that if he ever needs a date, just give her a call. (Is there a clause in Mr. Duchovny’s contract stipulating at least five tributes to his irresistible allure per episode?) Not allowed to have sex of any kind for 48 hours following the procedure, Hank spends most of the opening episode clutching his privates, administering ice, and swallowing Vicodin. To add to his discomfort, he’s also promised Karen that he will quit smoking, and is wearing a patch.

None of this prevents Hank from getting into trouble, however. If the first season of “Californication” was all about Hank’s wayward attempts to win Karen back (while sleeping his way through half of Venice Beach), the new season begins on a note of happiness fulfilled, and the strange tension that arises from the awareness that it may not last. Karen seems especially nervous, and no wonder, given the number of women in their circle she knows Hank bedded during his tenure as a single man, not to mention those she doesn’t know he slept with — like Bill’s daughter Mia (Madeline Zima), who is still hanging around, waiting to cause trouble. As for Hank, he has only to go to the supermarket to run into some impossibly gorgeous, half-remembered one-night stand sucking lasciviously on a crimson-tipped popsicle and offering to jump into bed with him once again.

But a whole new level of temptation arises when Hank, Karen, Charlie, and Marcy meet for drinks and run into another of Hank’s exes, Sonja (Paula Marshall), who is now the girlfriend of Julian Self (Angus Macfadyen), a bearded guru and author of a best-selling self-help guide titled “The Artist Within.” He’s easy prey for Hank’s sardonic wit, of course, but more important, he invites them to a party at the Laurel Canyon mansion of a legendary rock producer named Lew Ashby (Callum Keith Rennie). Before long, Lew has persuaded Hank to ghostwrite his long-awaited autobiography — working title: “Why Everything I Touch Turns to Gold” — and introduced him to a new universe of erotic possibilities, since his home is permanently stocked with drugs, booze, and girls. At this point, it’s hard to imagine how Hank and Karen are going to make it through more than a few episodes. Nor does one really hope for it, either — the show is more fun when Hank’s on his own.

Of all the additions to the cast, Lew — the long, lean, believably boyish prince of rock ‘n’ roll producers — is the most intriguing. He claims to be carrying a torch for a woman he spurned long ago for the sake of his independence. (“I wanted the freedom,” he tells Hank in a rare quiet moment. “Now I drink what I want, I snort what I want, and I f— what I want… Freedom — for what?”) But he seems eager for everyone around him to follow the path he professes to regret rather than the one he wishes he’d taken. Lew also talks Hank out of his oft-repeated nostalgia for New York, scolding him for being a typical East Coast snob and urging him to enjoy life in Los Angeles. It looks as though Hank is going to take his advice and follow the West Coast road to wherever it takes him.