"Between Two Women" (airing tonight at 9 on Channel 7) spins a totally preposterous tale of the tortured relationship between an ingenuous woman (Farrah Fawcett) and her twisted mother-in-law (Colleen Dewhurst). You know poor Farrah's in for a long haul when she nervously greets her mother-in-law-to-be with a sweet smile and a box of chocolates only to have the dragon spit out the chocolates and yank the girl to her feet so she can straighten the cushion on her lawn chair.

And that's just for starters. Farrah's marriage to the ever-so-sensitive Michael ("Flashdance") Nouri gets off to an inauspicious start with a severe case of coitus interruptus. It seems Mom had a yen to warm up the couple's honeymoon cabin with a pot of bouillabaise and a couple of insinuating remarks about Farrah's possible prenuptial promiscuity. On a family vacation, Mom wakes Farrah in the middle of the night, demanding that they swap hotel rooms because her air conditioning isn't working. She crashes a party Farrah throws for her aspiring painter hubby, fights for control of the radio dial and winds up screaming at the gallery-owning guest of honor. Just what the marriage counselor ordered.

It isn't long before the not-so-happy couple separates and the whole painful problem comes to a head. Unfortunately, the same cannot be said of the movie itself.

At an excruciating birthday celebration for her grandson, Mom becomes obsessed over her daughter-in-law's decision to wipe up a glass of wine spilled on the tablecloth. It seems that the Good Housekeeping Seal of Approval is bestowed only upon those who disrupt meals to change stained tablecloths. Mom initiates a shouting match bound to leave even the most tolerant viewer squirming, retires to an upstairs bedroom and has a stroke.

So does Farrah break out the champagne and begin toasting her good fortune?

Naw. She does what any woman in her position would do. She moves her comatose mother-in-law in to her home, ignores everything in her life to care for her night and day and shrieks at her husband for suggesting that they hire a nurse.

It is a testament to the flawless performances of Fawcett and Dewhurst that this movie is bizarre and discomfiting rather than a howler. Dewhurst's portrayal of the mother-in-law is a real chiller and Fawcett is alternately earnest and endearing. She even manages to carry off the melodramatic intermittent narration of a letter to her mother-in-law. Her only mistake seems to have been her willingness to trust executive producer-director-cowriter Jon Avnet, whom she so successfully teamed up with in "The Burning Bed."

The movie's worst offense is its shameful waste of the talents of two outstanding actresses on such a maudlin and ludicrous tale. One can't help but wonder what could ever have induced anyone to want to make this movie? Even more important, what possible reason could anyone have for wanting to watch it?