Marty, you see, is a grown-up twin. Although his sister, who thinks she is Jackie-O, is certifiably insane, Marty fits right in with the rest of this highly dysfunctional family in the witty black comedy THE HOUSE OF YES.

Mother and daughter, played in a brilliant performance by Parker Posey, are both varying degrees of wacko. Most dysfunctional families in the movies are more angry and mean-spirited than diabolically abnormal as this one is. The daughter's fantasy of being Jackie-O is probably the most sane part of her being. Mrs. Pascal is the sort that will not let Jackie-O keep a hairbrush downstairs since food is kept on that level. She explains to Marty's new fiancee, Lesly (Tori Spelling), soon after their first meeting that Jackie-O was holding Marty's private part when she came out of the womb.

The dialog by Wendy MacLeod, based on the play by Mark Waters, is so sharp and biting that it seems in danger of cutting through the celluloid at any moment. The script, reminiscent of a David Mamet play, flows smoothly with its fast paced intelligence and mesmerizing set of bizarre characters. The exaggerated setup has Lesly and Marty arriving at the family's out of the way mansion during a Thanksgiving Day hurricane.

In this storm are two sane individuals. The fiancee is a giddy, school-girl type, embarrassed by everything, a complete contrast to her rival Jackie-O's bitter pseudo-sophistication. As the two twins' younger brother, Anthony, Freddie Prinze Jr. plays the All-America boy type whose only foible is his explicit obsession of bedding his brother's fiancee that night.

"We all have our secrets," Jackie-O tells her potential sister-in-law, and boy, does she have a few. This is a house filled with them. (When Lesly calls it the family's "home" to Mrs. Pascal -- they've never had a visitor before Lesly -- Mrs. Pascal becomes discombobulated until she realizes that Lesly is talking about their "house.")

In a film that gives new meaning to the phrase, "made for each other," the twin's biggest, but not their only secret, is that they've had a long-term incestuous relationship. They don't like to discuss it, although they are not particularly ashamed of it. Perfect for viewers who can appreciate perverse comedy, this story never pulls its punches.

Jackie-O tries in many ways, few subtle, to show that she is a better match for Marty than that ditzy fiancee of his. In one scene Marty and Lesly are playing chop sticks together on the piano when Jackie-O pushes her aside and starts playing a challenging classical piece for four hands. Marty joins her as his fiancee looks on with envy.

The chemistry between Parker Posey and Josh Hamilton is nothing short of amazing. They put down their little brother and most of the other sane people in the world. Their ripostes are engaging filmmaking at its best. Director Mark Waters keeps the show's energy level high and lets the leads sling zingers at each other at a furious pace. His crisp direction ensures the movie has nary an ounce of fat on it.

Jackie-O is temperamentally incapable of being nice. And being jealous, she cuts Lesly down mercilessly. "Were you poor?" Jackie-O asks her when she finds that Lesly committed the crime of growing up impoverished. "Did you eat pies? Chicken pot pies?" "Pancakes actually, lots of pancakes," Lesly replies with her usual sincerity.

"A Donut King, so is she like the queen?," Jackie-O cattily inquires of Marty when she learns that Lesly works at a Donut King. "Are we entertaining royalty?"

With Rolfe Kent's whimsically sinister music it never seems clear where the story is headed. Will it end in a big emotional explosion, a murder, people slowly cutting each other up with words, a familial catharsis, a weather disaster or what? The emotionally charged play is clearly going somewhere, and the engaging characters captivate the audience with their spell. I'll not say more except that the ending is perfect and a bit of a surprise.

THE HOUSE OF YES runs a blazing fast 1:25. It is rated R for sexual situations and conversations, mature themes, violent overtones and some profanity. The movie would be fine for older and mature teenagers, i.e., treat the movie as it were rated NC-17.