Roddy Doyle, the Irish novelist and playwright who made his reputation with what he called his Barrydown Trilogy -- "The Commitments," "The Snapper," and "The Van" - has written a new film script that for some awful reason comes with the disastrous title "When Brendan Met Trudy." Has no one in Dublin heard of Harry and Sally? In any case it is his first original screenplay, and as a screenplay it's sketchier than it should be, with peripheral characters never given the kind of attention that would enrich the film and make it work. It seems as though Doyle just didn't care enough to polish his script.

The film is a light comedy; it has a charming premise and even a few nice laughs, but in addition to the sketchy script it's undone by two things: inept direction and a sadly wooden male lead. That lead is Brendan (Peter McDonald), a teacher in a Dublin private school. He's a shy young man who's almost given up on ever finding a woman. But he does find a woman, and the woman he finds is Trudy (Flora Montgomery); and although when they meet she tells him she's a Montessori teacher she is actually a midnight thief, a burglar who breaks into houses and steals the valuables; and she truly loves her work. Montgomery is far and away the best thing in the film, with a delicious sexiness and wonderful go-to-hell attitude.

In the course of the film she introduces Brendan to all of the sensual pleasures of life, not excluding the adrenaline rush that comes from pulling off a successful burglary, and although their biggest heist comes to a bad ending, we can be sure that they'll wind up together in life.

Doyle is a sophisticated and experienced writer of bittersweet comedies, and sketchy as this one is, and even though it doesn't have anything like the magic of "The Commitments," it still might have had a chance to win us over because it plays off the wonderful premise that when lust meets repression it is repression that will lose.

But where the film fails is, first, in its flat direction by Kieron J. Walsh, a first-timer who tends to stand his people up in front of the camera and let them read their lines, as though they're in a sitcom. He seems not to know that in a movie it is the camera that tells the tale, and not the actors. That is, what an audience sees must be only what the director wants us to see; otherwise we are looking at a filmed stage play. Walsh misses his opportunities for jokes, both physical and verbal, and his timing is so bad it keeps slowing the film almost to a halt.

Even worse is McDonald as Brendan. He seems to have stumbled in from some other movie - a tragedy, no doubt - and there is even a moment that plays off his hangdog look, when he's been called to his headmaster's office and slowly walks the long corridor to the sound of his rebellious students intoning "Dead man walking." It's hard to understand how the sexy, vital Trudy could ever bother wasting her time with this nebbish. McDonald has a flat, uninflected voice and an undefined, uninteresting face that holds no interest for an audience.