"Related" starts off in the middle of a conversation in the middle of a sisterly evening, a fast game of four-handed tennis that may leave you briefly wondering whether you've missed something. Who are these bantering blondes, and are you sure you can tell them apart?

The hour-long WB series, premiering tonight at 9 on Channel 50, tells the story of the Sorelli sisters, a quartet of young New Yorkers who are making their difficult-funny-stupid way through life. And the ratio of difficult to funny to stupid may have a lot to do with the length of their show's life.

Tonight's episode introduces the characters amid a lot of cutie-pie chatter but also effectively outlines their stories. Ginnie (Jennifer Esposito), the oldest, is a lawyer on the verge of making partner who's just learned she's pregnant but hasn't found a way to tell her husband, Bob (Callum Blue). Ann (Kiele Sanchez), a therapist who counsels transvestites, is on the verge of a split with her longtime boyfriend. Marjee (Lizzy Caplan) is a party planner who's going insane because her client wants to bring dogs to a venue that doesn't allow them.

Those three are the blondes. The fourth sister, Rose (Laura Breckenridge), is a brunet college student who's just changed her major from pre-med to experimental theater and is, like, finding herself. And in almost every one of her scenes, she seems to be beaming in from another show altogether.

So this is a series that wants to be all things to all viewers. You want a romantic comedy? Follow Ginnie and hope she finds a way to tell Bob her news before she goes into labor. Something more dramatic? Take Ann and her breakup. A silly comedy? Go with Marjee and the pugs. An idiotic comedy? You can't beat Rose for that, though you may wish you could.

Rose is supposed to be 19, but she acts 12 on a good day. Almost the minute she moves into her dorm room with a fellow experimental-theater major, she runs out and gets her tongue pierced. Okay, that kind of thing happens, but not to girls like Rose. She's so childishly petulant about her family's horror -- an affronted Brownie Scout -- that the scene falls apart. Later, she shows up at a fancy event with her hair dyed bright blue. Somebody on the "Related" team thinks this is hugely funny, and somebody is wrong.

The fault is partly Breckenridge's; she seems to have learned acting by studying the films of Shirley Temple. But the problem is deeper than that -- the creators are having trouble deciding what their show is about.

There's a tense early scene between Ann and her restaurateur boyfriend, Danny (guest star Dan Futterman). They're at his new establishment, they haven't had any time together for weeks, and she's just asked him, "Are we over?"

Sanchez and Futterman are just fine; they suggest the layers of time and feeling that this relationship would have. But hold on, here comes that darlin' Marjee with a breathless load on her mind:

"Oh Dan -- I am so glad to see you! Oh -- am I interrupting something? Danny -- you've just gotta save my life, like now. . . . They want to bring six pugs to this benefit that I'm doing tomorrow night. But the club that I booked for it -- they don't allow any animals. Guys from Long Island -- yeah, that's fine. But pugs -- anyway, now I have a benefit and no place to have it. And Danny, if you don't let me use your restaurant, I'm gonna be fired. Ridiculously fired!"

She goes on for quite a while longer as Ann stands by, looking pained. Marjee's interruption is meant to be charming -- an adorably dithery female in a jam, gootchy-gootchy-goo -- but in the context of the scene, she seems only creepy and clueless.

WB publicists, showing a gift for careful wording, describe the show as "from creative forces behind 'Friends' and 'Sex and the City.' " By that they mean that executive producer Marta Kauffman served the same function on "Friends" and executive consultant Liz Tuccillo had a hand in "Sex and the City." The strongest connection "Related" makes to those series in its opening episode is that its characters are all young, attractive New Yorkers.

The network did provide the second and third episodes for viewing, and there are signs that the show may be finding its feet a bit. (At least Rose dyes her hair back to its original color.) So who knows? If the writers can curb their case of the cutes, this sister act might have a future.

Related (60 minutes) premieres tonight at 9 on Channel 50.

Laura Breckenridge, left, Jennifer Esposito, Kiele Sanchez and Lizzy Caplan play sisters on the go in New York.Jennifer Esposito, left, Kiele Sanchez, Lizzy Caplan and Laura Breckenridge as the Sorelli siblings.