As far as cougars go, Naomi Watts and Robin Wright are pretty choice. Both radiant blondes, they're as tanned and toned as West Hills moms who spend their days taking spin classes at the Multnomah Athletic Club and shopping for organic grapefruit at Strohecker's. Their characters in Adore, a willfully ludicrous yet ultimately unsatisfying film, live in palatial seafront properties on an Edenic stretch of Australia's east coast. One's a widow; the other is essentially single, with her husband off teaching in Sydney.

Their much younger lovers aren't bad either—they're surfers, also tanned and toned and evidently averse to the feel of fabric against their perfect chests. One has brooding eyes and a mop of dark hair, the other angsty eyes and a mop of blond hair.

Watts' and Wright's characters are lifelong best friends, as are their Adonis-like lovers. There's just one hitch: This ménage à quatre is made up of two sets of mothers and sons in pseudo-incestuous pairs. The arrangement is both deeply icky and thoroughly implausible, and Anne Fontaine's Adore (based on a short story by Doris Lessing, written when the author was in her 80s) unfolds in an eerily detached, foreordained manner.

Watts and Wright play women so close to each other, both in terms of appearance and disposition, that others mistake them for a lesbian couple. They've raised their sons—who both have three-letter names and are easily confused—together. But when one son makes a move on the other's mom, the opposing son retaliates with his own cougar revenge sex. Yet no friction arises. "I don't want to stop," Watts says to Wright, in a sterling example of the screenplay's consistently on-the-nose dialogue. "I don't see why we have to." The boys have a meaningless scuffle in the surf, proof that they've still got some neurological development to go before they catch up with their mums.

So the relationships don't stop, in large part because both must continue in order for the greater dynamic to be sustained. But when some more age-appropriate lasses get tossed into the mix, Adore sloughs off the opportunity to say anything about intergenerational relationships, opting instead for very pretty scenes of very pretty people in very pretty settings. It also doesn't bother to examine the psychological impact of each relationship's end. It can't, in fact, because it never considered what each woman got out of the romance in the first place (regular orgasms and male attention aside). Watts' and Wright's skillfully nuanced performances prevent the whole affair from plunging into absurdist farce, but their characters are too narcissistic and detached to actually be interesting. There are times when behaving badly is the right thing to do. Adore is not one of those times.

Critic's Grade: C

SEE IT: Adore is rated R. It opens Friday at Living Room Theaters.