Jack Bauer (Kiefer Sutherland) returns in the heart-stopping season premiere of 24. But will he live to see the end of the day?

The return of 24 will give you a few minutes before your heart jumps through your chest.

About two and a half of them.

Without revealing anything, rest assured the acclaimed drama will grab your attention quickly tonight. And it won't let go through the back-to-back episodes that kick off Season 5 (8 p.m., Global, Fox).

Two more new episodes of 24 are scheduled to air tomorrow (same Bat time, same Bat stations).

Note to the uninitiated: If you never have seen 24 before, tonight is a great place to start. You won't understand every tidbit, but you won't feel lost. And you will have absolutely no trouble getting into it.

Kiefer Sutherland is back as Jack Bauer, a crack but controversial U.S. federal agent who, at the conclusion of the fourth season, had faked his own death and was walking off into obscurity. Only four people in the world knew that Bauer actually had not been killed.

When first we see Bauer tonight, 18 months have passed. He has a new name and is living a non-descript life, working irregular shifts at an oil field and renting a room in a home with a single mom and her teenaged son.

But with Sutherland signed on for another year, obviously events occur that drag Bauer back into action. However, Sutherland has hinted this could be his final season, so you shouldn't place your long-term bets on Bauer's survival.

Whether 24 could chug along without Sutherland is hard to say. There is something about him as an actor that gives him a degree of believability not only as a sympathetic figure, but also as a man of unshakable mental and physical strength.

You obviously need a suspension of disbelief to appreciate 24. For example, at one point during the second episode tonight, Bauer gets in and out of a crime scene in a condominium complex that is being blanketed by 167 federal agents.

That's right, 167 federal agents. Barring the invention of an invisibility potion, that might not happen in real life.

Ironically, some of Sutherland's most effective moments come when he isn't pulling off incredible stunts or outwitting a phalanx of armed suits.

There's a scene tonight when the aforementioned teenaged boy (named Derek, played by Brady Corbet) makes the mistake of following Bauer, much to Bauer's chagrin. Derek naturally sees some things he shouldn't see, and when he starts to whine, Bauer throws him up against the side of a van with the force of a professional wrestler.

"Let's get something straight, kid," Bauer says with a red-hot intensity that could melt walls. "The only reason you're still conscious is because I don't want to carry you."

Needless to say, Derek shuts up and gets into the van.

Not everyone can pull off such anger convincingly, but Sutherland can.

Likewise, not everyone can play crazy convincingly, but Jean Smart can. The veteran actress (Designing Women, Frasier) joins the cast of 24 as unstable first lady Martha Logan, and she clearly is the front-runner for best-new-character honours.

With Sutherland's future up in the air, it remains to be seen if 24 is on its last legs. Either way, those legs still are kicking, and your heart will be thumping.