HBO's semi-improvised 'Doll & Em,' CW's sci-fi drama 'The 100' premiere

* DOLL & EM. 10 and 10:25 tonight, HBO.

* THE 100. 9 tonight, CW57.

LARRY DAVID ("Curb Your Enthusiasm") and Emily Mortimer ("The Newsroom") don't seem to share much beyond HBO.

At least not until tonight, when Mortimer can be seen playing a less-than-flattering version of herself in a semi-improvised show of her own devising.

Not that she devised it by herself. The six-episode "Doll & Em," which will be shown in back-to-back episodes each Wednesday for the next three weeks, is Mortimer's collaboration with best friend and fellow actress Dolly Wells ("Bridget Jones's Diary").

Mortimer plays a successful British actress named Emily whose response to her lifelong friend Dolly's breakup with a boyfriend is to offer a trip to Hollywood and a job as her personal assistant while she makes a movie.

"The point of you being here is you being here," she explains to Dolly, who's trying to figure out what the job entails.

It's quickly evident that the quasi-friendship that may exist between stars and assistants is no match for actual friendship, and that an actual friend may not be the best choice when work's involved. Even if that work involves merely making sure the lattes come with extra foam.

Anyone in inside-Hollywood withdrawal following the season finale of Showtime's "Episodes" - whose recent take on cocktails-with-TV-critics was a horrifyingly accurate depiction of a weird part of my job - might want to check out "Doll & Em." It's no "Curb," but it includes cameos by Susan Sarandon, John Cusack, Andy Garcia and Chloe Sevigny. (Jenkintown's Bradley Cooper is in the opening credits, walking a red carpet with Mortimer.)

And it shows how easily even "nice" people can grow accustomed to being catered to, a process so insidious they may not even notice it (though it looks as if Mortimer and Wells have been paying attention).

The show, which premiered in Britain last month, isn't so much about show business as it is about friendship. It's at its best - if not necessarily its funniest - when Em and Doll are struggling to find a balance between their childhood selves and the more demanding adults they've become.

There's nothing very original about the CW's new sci-fi drama "The 100" (other than its insistence on being pronounced "The Hundred"), but it's execution that counts.

Or executions.

There are no beheadings - this isn't "Reign" - but capital punishment's a big part of the oxygen-deprived future envisioned in this series, which takes place nearly a century after a small group of humans fled a poisoned Earth to live, "Battlestar Galactica"-style, in a space colony with a justice code that makes nearly everything a capital crime, at least for adults, who can be "floated" into space.

Delinquent juveniles have been spared, but with the air running out, a hundred are sent earthside, to be be used, like canaries in a coal mine, to see if Earth is ready to sustain human life.

You don't need "Lord of the Flies" to tell you this won't go smoothly, but "The 100," the latest book-TV package from young-adult fiction factory Alloy Entertainment ("The Vampire Diaries," "Pretty Little Liars"), is as ruthless as any high-end cable drama in its willingness to sacrifice almost anyone, adult or juvenile, to keep our attention.

Isaiah Washington ("Grey's Anatomy"), Henry Ian Cusick ("Lost") and Paige Turco play leaders with very different approaches to the politics of scarcity, while Eliza Taylor is Clarke, a good girl in a bad place.

Yes, it's a CW series, but one that poses enough lifeboat-ethics issues to keep a freshman philosophy class busy for months.

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