Deep End of the Ocean," an emotion-ridden look at what happens when a child is snatched away from his parents only to reappear nine years later, is as heartfelt as it is shallow -- an affecting piece of cinema whose effect dissipates quickly under careful scrutiny.

Of course it's affecting; how difficult is it for a film about parents who lose their child to be affecting? And it features a wonderful performance from Michelle Pfeiffer, whose mother seamlessly goes from carefree to devastated to barely hanging on. Hers is a believable, wonderfully nuanced performance that largely avoids the obvious histrionics. Come Oscar time 2000, don't be surprised to see her name on the Best Actress list.

But "Deep End of the Ocean" is also one of those maddening films where you wish just one character would display a few ounces of common sense. Much of the film's tension derives from family members who never talk to one another, who deal with emotional crises by staring within themselves and wondering what's wrong with everyone else. Not that such people don't exist, but having a whole family of them strains credibility.

Based on Jacquelyn Mitchard's best seller, an early pick for Oprah Winfrey's famed book club, the film opens with Beth Cappadora (Pfeiffer) dragging her three young children to Chicago for her high-school reunion. Within minutes of her arrival at the hotel, her middle child, Ben, vanishes.

All sorts of searches ensue, first by her fellow classmates at the hotel, then by the police (led by Whoopi Goldberg, whose character must have ended up mostly on the editing room floor), then by an army of volunteers. Beth struggles to maintain hope, but something inside her keeps insisting there is none. When months pass and Sam hasn't turned up, Beth finds little consolation in knowing she was right.

In fact, Beth finds little consolation in anything. Her other children become an afterthought, husband Pat just a reminder of the horrible mistake she made, her career as a free-lance photographer a hollow waste of time and effort. Just existing from day to day becomes a chore, a fact Pfeiffer best evinces through her eyes and her demeanor. She does less well in a cliched Christmas scene, in which her family's insistence on pretending that nothing has happened finally makes her snap and start yelling.

As Pat, an underused Treat Williams' main job is to look helpless as his wife descends into melancholia.

Nine years pass. Beth has come to an uneasy truce with life, Pat has opened the Italian restaurant of his dreams, elder son Vincent is threatening to become a juvenile delinquent. And then one day, this kid shows up at the front door, asking if the Cappadoras need their lawn cut. Beth recognizes him immediately as her long-lost son.

At this point, the film introduces what could be its most interesting character and possibly its most tragic: George (John Kapelos), the man who was unfortunate enough to raise Ben (whom he calls Sam) without realizing he was another couple's child. The film is so busy chronicling Beth's emotional journey, it pretty much dismisses George as an afterthought. But here's betting audiences won't do the same.

Can Ben/Sam (nicely underplayed by Ryan Merriman) re-connect with the family he never knew? Can Beth and Pat really act in Sam's best interests? And how will getting his brother back affect Vincent, who's spent his life a distant runner-up when it comes to his parents' affections?

All of these are good questions, but "Deep End of the Ocean" lets the answers come far too easily. Good performances can't hide the film's paint-by-numbers approach to its moral quandaries. If only tragedies were this simple.

'Deep End of the Ocean'Starring Michelle Pfeiffer and Treat Williams

Directed by Ulu Grosbard

Released by Columbia

Rated PG-13 (language and thematic elements)

Running time 110 minutes

Sun score ** 1/2

Pub Date: 3/12/99