"24,” the evolutionary ancestor of serialized dramas like “Lost” and “Heroes,” sounded like a longshot when it first premiered back in 2001. But it quickly grew on viewers, commanding week-to-week loyalty, and after five seasons it broke out last year as an  Emmy winner, garnering Best Drama and Best Actor for Kiefer Sutherland.

They were both rightly deserved. "24's" writers have a singular genius for building and sustaining dramatic tension through each hour of multiple plot twists and ticking-clock deadlines, and doing it in a way that masks the reality that the storyline will work itself out not that night or the following week but over the entire season. It's a good trick.

The action is anchored by Sutherland as Counter-Terrorism Unit agent Jack Bauer, a man who is willing to do anything to protect America, no matter how morally questionable.

The risk with such characters is that they burn out, use themselves up, and it invariably happens some time after the audience has tired of the demands of their intense personalities.

Sutherland's particular genius as an actor has been in his ability to sustain the believability of Bauer without sacrificing any of his intensity. He's perfected over five seasons Bauer’s balance of steely resolve and inner turmoil. He's been shot, stabbed, electrocuted, tortured and haunted by the deaths of countless family, friends and colleagues, and by all rights Bauer should probably be permanently institutionalized. Yet Sutherland has sustained the uber-agent believability as a rational man functioning in an irrational, treacherous world.

Now back to the question: After a superb fifth season, can “24” make it work for a sixth, which premieres with two episodes on Sunday and two on Monday before returning to its regular 9 p.m. Monday timeslot?

If the first four episodes are any indication, the answer is yes, quite.

Sutherland is more determined and tortured than before. The plot, always a twisty pretzel, goes through untold convolutions in a matter of the few hours of those early episodes, and Bauer darts through them.

Life hasn’t gotten much better for our uber-agent. Returned to the U.S. after two years of torture at the hands of the Chinese, Bauer is to be turned over by CTU to a turncoat terrorist in exchange for the whereabouts of another terrorist who has been planting bombs in major American cities for weeks.

Of course, as one would expect, Bauer discovers that things aren’t as they seem. He departs on his mission to determine the real truth.

Some of the old gang are around to help him uncover that truth, including sarcastic analyst Chloe (Mary Lynn Rajskub) and ever-steady CTU chief Bill Buchanan (James Morrison).

New to the cast are Peter MacNicol (“Ally McBeal”) as privacy rights-averse presidential chief of staff Thomas Lennox and Regina King (“Jerry Maguire”) as civil rights attorney Sandra Palmer, who also happens to be the president’s sister. Those new additions, both stellar actors, provide a nice counterpoint to the Bauer-based action.

Unfortunately, D.B. Woodside (“Buffy the Vampire Slayer”), as President Wayne Palmer, is less convincing. Even in “24’s” alternate universe, it’s hard to buy that a guy who, in recent seasons covered up an affair/murder/suicide and later hid in the woods from would-be assassins, has now rise to become the leader of the free world.

But one advantage of a show like “24” is that it need not worry too much about explaining such implausibilities, of which there are many. The breakneck pace just won’t allow for mulling over plot holes.

“24” may have paved the way for the epic “Lost” but unlike its amazingly ambitious descendant, it prefers to stay lean rather than fritter away time dwelling on the meaning of things.

One might think the writers, after a season in which the president was revealed as a traitor and at least five major characters died, some of whom had been around since the first season, would ease the pace in season six. They have not. By the end of the fourth episode, at least one major character has been killed in shocking fashion and an event has occurred which, even by “24” standards, is stunning.

If the rest of the season lives up to the first four hours, season six could be "24's best yet.