Pets brained with blunt objects, toddlers gurgling for help in icy waters, small children lobbed off precipices: The Good Son is good clean fun. Despite the promising subject of a sweet-talking grade-scool psychopath, plenty of mollifyingly gratuitous violence, fine acting, and tension, the film is dull. Not knowing with precisely which weapon the final duel will be fought does not constitute suspense.

Discerning aesthetes might make the pilgrimage to The Good Son for the sake of respected British author Ian McEwan's screenplay, prepared stoically to endure the vicissitudes of Macaulay Culkin, commercialized American cinema and Hollywood's uncomprimising compromisal of artistic integrity. They will be disappointed. Contrary to expectations, it's the director and actors who make the most of a lukewarm script.

The film addresses that insoluble question: how to persuade the rest of the world that the adorable wee lad is actually evil incarnate? Mark (Elijah Wood) goes to stay with his aunt and uncle on the death of his mother. A few days of rougher-and-tumblier-than-expected play with his cousin Henry (Macaulay Culkin) convince him that he is skating on thin ice, at times literally. But to grownups, Henry appears so harmless, and Mark himself has been acting so unstable since his mother's death, that no one will listen to him. Will Mark wrench the scales from the world's eyes, or will Henry hoodwink humanity with his sheep's clothing?

The audience knows the conventions of the genre: Henry will perpetrate a few grisly crimes; Mark will bang his head against the wall of parental disbelief; the stakes will keep rising until the final cliffhanging confrontation (again, literally). Far from defying Hollywood cliches, McEwan endorses them wholeheartedly. Flushed children skating merrily on the millpond when all of a sudden...; better yet: a clifftop tussle with the sea roaring on the ragged rocks below, and to top it all: Sophie's choice--a child dangling from either arm, and not enough strength to hold them both.

McEwan fleshes out this skeletal scenario with a hearty dose of psychobabble. Freudian guilt complexes, Buddhist cycles of reincarnation and wells of spiritual self-empowerment roam the script untamed. But eclectic psychodramatic conceits are no substitute for substance.

Furthermore, the over-ambitious dialogue places undigestible speeches in the mouths of our tiny tot protagonists. I'll buy a stunning transition from cute kid to devilspawn, but Macaulay Culkin saying "Don't fuck with me" is just a bit too much to swallow.

Meanwhile, Culkin himself acts precociously. He realizes that casual deadpan in a ten-year-old looks far more sinister than sidelong glances and wicked cackles, and so plays it straight. Culkin's calm in turn forms the perfect foil to the frenzied indignation of Wood, his fearless adversary. Splattered with tomato juice, frenetically pumping squash down the disposal, Wood manages to look far more twisted and dangerous than Culkin ever does. The dynamic of this role-reversal, excellently acted by both Wood and Culkin, generates all the tension in the film. The pair carries the production; all other players are secondary.

Indeed, director Joseph Ruben conspires to keep the spotlight on the young prodigies and off everyone else. The adults (Wendy Crewson, David Morse, Daniel Kelly, and Jaqueline Brooks) are competent and unobtrusive. The filming emphasizes realism and immediacy instead of effects; this reviewer didn't even notice a soundtrack. The direction was notable for its minimalism.

Ruben did interrupt the flow of the film when he overplayed the early moments of tension. If the whole audience knows from the start that Culkin plays an undercover killer, then it's none too tricky to produce tense moments auguring imminent disaster. Ruben dwells on each scary mask, toy gun, and childish threat, until Culkin's every mouthful at dinner appears redolent of latent monomania.

These moments stick out only because the film normally progresses so smoothly. On that score the actors and crew deserve congratulation. But their streamlined performance highlights a script that is smooth going on downright flat.