Chris Haston, NBC Universal
Melanie (Erinn Hayes) and her mother (Nancy Lenehan), are startled when Sam (Kyle Bornheimer) shows up wearing only a plastic bag.

BEVERLY HILLS, Calif. — Pilot episodes are not always a sure indication of the TV series that is to follow. Because sometimes producers have come up with a first episode that's going to be impossible to replicate on a weekly basis.

This year's top candidate to win the Can't Ever Do That Again Award is CBS's "Worst Week," which premieres Monday at 8:30 p.m. on Ch. 2.

It's all about the guy with the worst luck in the world. Sam Briggs (Kyle Bornheimer) is a likeable guy who's in love with Melanie (Erinn Hayes). But her parents, Dick (Kurtwood Smith) — a conservative judge — and Angela (Nancy Lenehan) don't like Sam at all. Which isn't going to make it easy to tell them that Melanie is pregnant and she and Sam are planning to get married.

And it doesn't make things any easier when Sam leaves a trail of unbelievable disasters in his wake. Suffice it to say that when he shows up at his future in-laws house wearing nothing but a diaper fashioned from a plastic bag, the trouble has barely begun.

Monday's pilot is filled with sight-gags and a remarkable string of events ... so remarkable that it's difficult to imagine that executive producer Matt Tarses and his team will ever be able to string anything together like that again.

"I think the goal is to, yeah, to try to maintain that," Tarses said. "That's what the show is. A friend of mine asked me, 'Well, he's not going to step in it every week, is he?' And the answer is, 'Absolutely, yeah, he is.'

"I mean, that's what we're going to do or we're going to set out to do. And the trick will be figuring out ways to keep it fresh and keep it surprising and interesting."

Yeah. That's the trick. Or, perhaps, the daunting challenge.

At least to begin with, Tarses and his team have plenty of source material. "Worst Week" is the Americanization of the British comedy "The Worst Week of My Life," and Tarses said "90 percent" of his pilot is adapted from the British show. "I used their script a lot. It was a great script."

"The tea and crumpets scene has been cut," joked Bornheimer.

But the British series can only carry its American counterpart so far. It ran for two, seven-episode seasons. Even when you throw in the three-part Christmas special, that's only 17 episodes — five fewer than the 22 episodes that's a standard season for an American sitcom.

(Not that there's any guarantee "Worst Week" will last an entire season.)

But Tarses said he's not worried about running out of ideas because friends, family and acquaintances are already inundating him with horror stories.

"Yeah. I can't get away from people," Tarses said. "It's a great discovery when you're out there talking about the show because people interrupt you immediately to tell you the things that have happened to them. It's really nice."

Whether there's enough material to keep this thing going remains to be seen. Apparently, the fallback plan is to have Sam break stuff.

"Let's just say that Dick ... has many things that mean a lot to him, and all those things are sort of up for grabs," Tarses said.

Yes, this sounds like an iffy proposition.

JIMMY MULVILLE, who produced the British version of the show and is an executive producer of the American version, said there's one big difference between the two.

"On the grounds that this won't make it across to the U.K., this cast is much better than our cast. But you pay peanuts in England, and what do you get?" he joked.

"I will deny that if that winds up back in England."

E-mail: [email protected]