Some things may go great together (like chocolate and peanut butter), but there are many, many more that don't — like the two storylines that eventually intersect in "Afterglow," a muddled drama about a pair of married couples living in modern-day Montreal.

It's easy to see what writer/director Alan Rudolph was aiming for with the picture — examining what effect having children (or not having them) can have on a marriage. However, it would have been a more interesting film if he had just concentrated on one of the storylines, the one about aging B-movie actress Phyllis (Julie Christie) and her philandering handyman husband, Lucky (Nick Nolte).

It's not as though the actors don't try. Christie and Nolte both give great performances (especially Christie), but they're undermined by Rudolph's ludicrous, too-convenient plotting and some awful affected performances by younger co-stars Jonny Lee Miller ("Trainspotting") and Lara Flynn Boyle (TV's "The Practice").

Miller and Boyle play Jeffrey and Marianne, a yuppie couple with some different ideas about how their relationship should progress. Marianne is pushing the frigid Jeffrey to start a family, while he . . . well, the way he's played, we're never quite sure what he wants, though it definitely isn't a child.

As for Lucky and Phyllis, they have been living in enmity since their daughter abandoned them — a move that has forced him to look for comfort elsewhere and which has turned Phyllis into a hypochondriacal recluse trying to relive her glory days.

In a plot development that seems straight out of a daytime soap opera, Marianne and Lucky meet and start carrying on an affair. And Jeffrey and Phyllis, who both suspect their spouses are cheating on them, bump into each other and begin a serious flirtation of their own.

However, neither "twist" is even slightly believable.

And that's too bad, since Christie is so good. (Nolte is almost her match, despite his ridiculous hairdo.)

"Afterglow" is rated R for simulated sex, including a lengthy scene between Nolte and Boyle, a violent fistfight, scattered R-rated profanities, some vulgar sexual double entendres and brief female nudity.