's Michael Ausiello has learned that Season 7 of 24 promises to be its most tense yet -- at least on the set.

Executives at the Fox hit, reports Ausiello, have scrapped virtually their entire story line for the season, delaying the start of production by roughly three weeks. According to sources, the 11th-hour time-out was called after the network put the brakes on a costly plan to shoot a number of episodes in Africa. Producers briefly toyed with the idea of finding a location in Los Angeles that could substitute for the continent, but they ultimately decided to ditch the whole concept and start over from scratch.

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Although a 20th Century Fox spokesperson declined to comment, 24 's expert scowler, Mary Lynn Rajskub, confirms that the clock for Day 7 has been reset. "I don't know what's going on over there, but they're going crazy," says the scene-stealer, who only learned last week that Chloe would even be returning. "We usually start [back up] at the end of July, and I don't think we're starting until a couple of weeks into August now. It's kind of exciting, because I think [the postponement] means that they're really having to dig in there and come up with new stuff."

The show's creative team was no doubt already feeling the pressure: Day 6 was considered to be about as explosive as a wet firecracker, so for Season 7 they really needed a plot that was incendiary. In fact, news of the setback comes on the same day the semiannual Television Week critics' poll named 24 the second worst show on TV, behind ABC's best-not-traveled October Road.

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