Laura Linney

Much of the credibility of "P.S." depends on whether the audience can buy into the onscreen May-December relationship between Topher Grace and Laura Linney.

Both are fine actors, and both give the type of performances that would normally convince you that their relationship is genuine. But it's the way in which their pairing occurs, the swiftness with which it occurs, that strains credibility.

Not to give too much away, but that initial pairing happens within the first 15 minutes of this comedy-drama, a very early juncture for a film to challenge the audience. Still, there's no denying that the two leads do their best to make it work.

Linney stars as Louise Harrington, a divorced art instructor at Columbia University who has some serious relationship issues. She's trying to resolve them as she gets more and more deeply involved with F. Scott Feinstadt (Grace), a graduate school applicant who bears the name and a physical resemblance to her long-lost childhood sweetheart.

This makes her question whether she's with him because of some genuine attraction and affection, or whether she might be trying to come to terms with the death of her first love. She also wonders if this new F. Scott might actually be her old F. Scott reincarnated. At the same time, her ex-husband (Gabriel Byrne) is still a constant presence in her life, as are some troublesome family members.

On the surface, this material bears some resemblance to the recent Nicole Kidman film "Birth." But at least here it's done with more humor, if not with any more smarts or taste.

However, director Dylan Kidd and co-screenwriter Helen Schulman (who adapted her own novel) do take a few wrong turns with the story. In particular, a subplot involving a "triangle" between Grace, Linney and Marcia Gay Harden's character is nearly disastrous. (The usually dependable Harden's over-the-top performance is a real false note in a film that can't afford one.)

Still, Linney and Grace are both very appealing. That the film works as well as it does is largely due to their performances.

"P.S." is rated R for occasional use of strong sexual profanity, simulated sex and other sexual contact, brief female nudity (and some nude artwork), and some vulgar sexual talk. Running time: 99 minutes.