LOS ANGELES – The shorthand theme for the fall television season: “To be continued … maybe.”

Inspired by the creativity – or at least the ratings – of “Lost,” “Desperate Housewives” and other shows with open-ended episodes that carry viewers from one week to the next, the broadcast networks have become serial junkies.

Brace yourself for dramas with intricate, ongoing plots about kidnappings, novice superheroes and fugitives from justice, all easier than ever to follow with TiVos, webcasts and iPods banishing any excuse for missing episodes.

And therein lies the problem.

Just when you’re truly hooked by the dangling story lines and emotional dilemmas, odds are that many of the shows will be canceled. You’re unlikely to learn the ending, happy or otherwise, because you didn’t have enough company in the Nielsen ratings.

“There’s been a lot of backlash about shows that viewers get invested in and then they end before the ending, like (last season’s) “Threshold’ or “Reunion,”‘ said analyst Shari Anne Brill of ad-buying firm Carat USA. “I’m still annoyed that I never knew who the hell “John Doe’ was.”

Brill’s chagrin over the truncated 2002-03 Fox series about a mystery man with encyclopedic knowledge (starring Dominic Purcell, now on the run in Fox’s “Prison Break”) shows how long viewers can hold a grudge.

Given that this is one of the best-reviewed seasons in years, the heartache could really endure.

33 percent solution

The cruel reality is that nearly one-third of new fall series will be off the air by January, according to Brill’s calculations. That’s not unusual: Of the 57 major broadcast network series that debuted last season, only 26 percent are back this year.

But the success of Fox’s “24,” which follows a day’s events over the season, and ABC’s “Lost,” which is weaving an elaborate story over not just episodes but years, led to TV’s typical follow-the-leader mind-set even at the risk of alienating fans of failed serials.

“Whenever we have a style or approach that’s successful” it gets copied, said analyst Bill Carroll of ad-buyer Katz Television. “We’ve gone from the age of the procedural to the age of the continuing drama.”

Crime dramas “Law & Order” and “CSI” and their spin-offs, which wrap conflicts up neatly within each episode, remain popular. But it’s complex, twisting plots and layered characters that have the momentum.

‘Vanished,’ ‘Runaway,’ and ‘Kidnapped’

So among the season’s 12 new dramas are Fox’s “Vanished,” with a senator’s wife gone missing; NBC’s “Kidnapped,” about the abduction of a rich kid; new network CW’s “Runaway,” with a family on the run after the dad is accused of murder; ABC’s “The Nine,” which follows the aftermath of a hostage crisis, and NBC’s “Heroes,” about regular Joes and Jills given superpowers.

There are newcomers of a different stripe with considerable buzz, including NBC’s “Studio 60 on the Sunset Strip,” which marks the return to TV of “The West Wing” mastermind Aaron Sorkin, and ABC’s telenovela-flavored “Ugly Betty.”

If this is a new golden age of drama, as critics and industry insiders consider it, that’s borne out at least numerically: In all, there are 50 new and returning dramas this fall on ABC, NBC, CBS, Fox and CW (the product of the merged UPN and WB).

By contrast, the introduction of nine new comedies will bring the total number to just 23, far less than the 42 sitcoms that tried for laughs last season.

Among them is “30 Rock” which, along with “Studio 60,” makes a pair of NBC shows that are inspired by the network’s long-running variety show “Saturday Night Live.”

The hourlong comedy “Ugly Betty,” based on Colombian telenovela “Yo Soy Betty La Fea” and starring America Ferrera (“Real Women Have Curves”) as an unchic young woman adrift in the fashion world, has earned critical praise.

Telenovelas, limited-run soap operas, have been highly successful in the United States on Spanish-language networks such as Univision and Telemundo.

While “Ugly Betty” has designs on more than one season, programs that hew closer to the traditional telenovela format are the mainstay of debuting MyNetworkTV, the Fox-owned answer for those WB and UPN affiliates left out when CW formed.

“Desire” and “Fashion House” are airing each weekday on MyNetwork, to be replaced after 13 weeks by other novelas. The question is whether English-language American viewers will take to the genre as the rest of TV viewing world has.

The other newcomer, CW, also faces hurdles – as do its viewers. Although returning shows like WB’s “Gilmore Girls” and UPN’s “America’s Next Top Model” make up much of the CW schedule, the shows may require some detective work to find.

Effort may be required to find a few returning shows on other networks because of scheduling shenanigans.

‘Grey’s’ vs. ‘CSI’

The most daring change shifts ABC’s hit medical drama “Grey’s Anatomy” from Sunday to a Thursday-night showdown opposite CBS’ veteran powerhouse “CSI: Crime Scene Investigation” (which prompted NBC to bump “Studio 60” from its announced Thursday slot to Monday).

‘Earl’ vs. ‘Betty’

NBC is pairing comedies “My Name is Earl” and “The Office” at 8-9 p.m. EDT Thursday against shows including “Ugly Betty” and CBS’ “Survivor: Cook Islands,” which this year is kicking up controversy with ethnically segregated teams.

Other big changes: CBS has ended its Sunday movies after more than two decades and, on NBC, Sunday night now means NFL football.

Fans also will have to brace for time-slot sharing as networks try to avoid annoying repeats. The examples include “Lost,” which will take a three-month break after six episodes for newcomer “Day Break,” and NBC’s “ER,” stepping aside temporarily for “The Black Donnelleys.”

There will be a measure of reassuring familiarity as veteran TV actors join returning shows or get new homes of their own this season.

Those familiar names

Camryn Manheim (“The Practice”) is coming to CBS’ “Ghost Whisperer,” Peter MacNicol (“Ally McBeal” and currently part of CBS’ “Numb3rs”) is joining “24” and John Stamos (“Full House,” “Jake in Progress”) will don a stethoscope for “ER.”

Among the many new series’ stars with a TV pedigree: Calista Flockhart (Ally McBeal herself) and Sally Field (“The Flying Nun”) on ABC’s “Brothers & Sisters”; Ted Danson (“Cheers,” “Becker”) on ABC’s “Help Me Help You”; Gerald McRaney (“Major Dad”), CBS’ “Jericho”; Jeri Ryan (“Boston Public”), CBS’ “Shark”; Leslie Hope (“24”), “Runaway”; Ron Livingston (“Sex and the City”), Fox’s “Standoff”; Gale Harold (“Queer as Folk”) and Ming-Na (“ER”), “Vanished.”

Others to look for: Matthew Perry (“Friends”), Bradley Whitford and Timothy Busfield (“West Wing”) on “Studio 60″; John Lithgow (3rd Rock From the Sun”) and Jeffrey Tambor (“Arrested Development”), NBC’s “Twenty Good Years”; Dana Delaney (“China Beach”) and Jeremy Sisto (“Six Feet Under”), “Kidnapped”; Victor Garber (“Alias”) and Eamonn Walker (“Oz”), Fox’s “Justice.”

From movieland

A handful of actors best known for their movie work are dipping a toe into TV, including Connie Britton (“Gladiator”), joining NBC’s “Law & Order: Special Victims Unit” and Eric Bogosian (“Wonderland”) new to “Law & Order: Criminal Intent”; Hope Davis (“American Splendor”) on ABC’s “Six Degrees”; Delroy Lindo (“The Cider House Rules”), “Kidnapped”; Ray Liotta (“Goodfellas”), Virginia Madsen (“Sideways”) and Simon Baker (“The Devil Wears Prada”), CBS’ “Smith.”