It isn't believable, but that doesn't matter. It isn't well written, but that doesn't matter. It has a few good scenes, but that doesn't ruin it. "Berrenger's," a soap in a liquid dispenser, premieres on Channel 4 tonight at 9:30, and it may just be golly-awful enough to catch on.

NBC has never been able to come up with a successful serial drama in prime time, so the network went to Lorimar, house of such ill reputes as "Dallas" and "Knots Landing," for this stir-fryer about a posh, successful department store and the scheming family that owns it. There's a megalomaniacal patriarch, there's a glamorous daughter, there's a Cain, there's an Abel, and there's a long, long trail a-winding.

On the premiere, writer Diana Gould drops in the viewer's lap a pot o' plot threads all tangled and gnarled. Most of the real gnarling is done by the patriarch: Sam Wanamaker as Simon Berrenger, who owns -- no, not Wanamaker's -- Berrenger's, although, we learn, it's his one-year-dead wife Sarah who really had the knack for empire-building, and a compassion totally beyond her boorish spouse.

Indeed, Simon is so contemptible in the extreme that it's surprising no one considers putting a bullet through his head before the third commercial. J.R. Ewing is Sammy Subtle by comparison. So is Darth Vader, come to think of it. Simon is beastly to his children, even the nonvenomous ones, an outright crook, a sex- ist, a -- to quote one son -- "miserable old cretin." He seems guilty of everything but cannibalism. Gould has made him so evil that he is uninteresting, and Wanamaker has none of Larry Hagman's hokey-jokey sex appeal. Nor would Simon ever have the wit to say, as I'm told J.R. said not long ago on "Dallas," "Once you've lost your integrity, the rest is easy."

But oh Lord, what's the difference? The audience for this sort of entertainment wants, apparently, pretty clothes and glittery grief. "Berrenger's" dishes all that up and serves it flambe'. Good son Paul (Ben Murphy) is aghast that Dad wants to merge the business with the tacky Trans-Allied empire (Cesar Romero plays its dapper major domo), much as he merged Paul with the wife he despises (Andrea Marcovicci), who is heir to an importer's fortune and whom Paul now seeks to shed for all the comforts of the home of marketing vice president Shane Bradley (Yvette Mimieux, growing nicely into those Lee Remicky roles).

Meanwhile, flunky Todd Hughes (Art Hindle) is conspiring with natty brigand Danny Krucek (model Jack Scalia) to stage a coup when the merger transpires and attempting to foist off cheapie TVs as genuine Sonys (!!!) on unsuspecting customers at the family's other store, out there in the suburbs, where it's feared that a Chinese-themed promotion might upset the lumpen bourgeoisie mit the credit cardtzen. Pretty but porcelain Laurel Hughes (Laura Ashton) confuses everyone with her Ms. Hot-and-Cold routine, hopping into bed with a man and then going into a hysterical snit fit in the morning when he tries to peek at her miscellaneous epidermis. What is she hiding under the lingerie? We must wait for another episode to find out. I predict she is a former Siamese twin worried that someone will see her separation scars.

That leaves the option of her twin showing up and wreaking havoc, which with this crowd isn't easy. Wreaking havoc here is like tryingto convert Republicans to capitalism.

As required by unwritten network law, one pivotal character is an impossibly wide-eyed (we're talking two football fields) innocent from Marion, Ohio (Leslie Hope), who is awestruck even at the sight of a perfume counter on her first day at work and who announces she is rejecting as tedious precisely the kind of life that most of the people who will watch "Berrenger's" are living (they seem to love that as much as they love seeing the rich claw and writhe). The perky lass decides she'll give not only the time of day but the time of night to that philandering John Higgins (Jeff Conaway, having a guilty good time hamming it up), a window dresser, even though she's warned by ex-flame Stacey Russell (Jonelle Allen) that he treats women like film to be dropped off at a Fotomat.

The three moderately effective performances in this menagerie are those of Anita Morris as the violently red-haired Babs Berrenger, a vulnerable sexpot utterly devastated when her monstrously insensitive father dismisses her plans to enter the fashion business by saying, "Look, nobody expects anything from you"; Robin Strand as Billy Berrenger, the resident drinks-too-much, indebted-to-hoodlums playboy son; and Eddie Velez as Julio Morales, the designing designer who says innocently, "All my life I've been dressing and undressing people in my head."

Often the actors seem to be losing interest in the lines as they say them, which increases your respect for them as human beings immensely, but now and then the show sets off a stupid spark or two, and when the good son and the bad dad have their last-act confrontation, a startling donnybrook in Dad's office, there's cause for arresting alarm.

Whether a sufficient number of Nielsen families will want to make "Berrenger's" a habit is the kind of unimposing question best left to "Entertainment Tonight" and USA Today. It appears to have the proper mixture of preposterousness and sheerest idiocy, but Saturday doesn't seem just the night for this kind of nasty whoopee. For what it's worth, the show, executive-produced by David Jacobs and Stuart Sheslow, could very well be -- and, true, this is splitting hairs -- worse, but as so often happens in TV, if it were any better, it would be boring. The Bounder'

In "The Bounder," a 1982 British TV series that begins a Washington run tomorrow night at 10 on Channel 26, a lovable cad pops out of prison and sets up housekeeping with his sister and her husband (hence the premiere's title, "He's Not Heavy, He's My Brother-in-Law") for a spell that promises to be quietly rollicking and easy to take. It's a drawing-room situation comedy, and you don't get many of those.

Not riotous like "Fawlty Towers" but probably funnier than "To the Manor Born" or "No, Honestly," "Bounder" depends on the considerable scoundrelly charm of Peter Bowles as Howard, the ex-con sent up on some sort of nasty embezzling business. Bowles is a towering bounder, among other things -- he's a tall, old, British Bill Murray, devilishly agile at getting the pretty rich widow next door (Isa Blair) to believe he was not in prison but in Zimbabwe, and at convincing one and all that the disappearance of his faked limp can be chalked up to nothing-if-not-mercurial divine intervention.

George Cole and Rosalind Ayres play the real-estate agent and his wife who take Howard in, till death them do part, or so it begins to appear. "Are you ashamed of me, Trevor?" Howard asks the husband. "Yes," he says. But like Paul Ford's Col. Hall to Phil Silvers' Sgt. Bilko, Trevor is forever frustrated in his attempts to catch the con man in mid-scam. Vernon Laurence produced and directed, Eric Chappell wrote and Tony Vivaldi composed the title tune for this droll, civilized and trivial amusement.