When a guy is sad day after day like Bruce Willis's character in "Unbreakable," you could suggest Prozac--which would not get to the root of the problem--or you can explore with him The Big Question: "Who are you?" By this we don't mean the "who are you" as in "The 6th Day," which features an Adam Gibson wondering whether he is really Adam Gibson or just the man's clone. We mean this in the sense of "what are you here for?" or more specifically, "Considering the genes you inherited and the upbringing you received, what should you do with you life to make yourself happy?" David Dunn (Bruce Willis) hasn't the foggiest idea.

In M. Night Shamalyan's "Unbreakable," which the 30-year- old director began writing even as his "The Sixth Sense" was being introduced, David is in bad shape. His marriage is on the rocks, his lovely and intelligent wife Audrey (Robin Wright Penn) sleeping in a separate room to the dismay of their precocious son Joseph (Spencer Treat Clark).

What can he do? Now, I suppose we all hope that some day, some Big Event will occur that will brush away the cobwebs of our lives, some transcendental experience that will cause us to begin anew with a fresh awareness of what our lives are all about. Sadly, this never happens to most of us. But while the underachieving David Dunn--a college grad who has settled for the job of university-based security guard--is riding the rails back to his Philadelphia home, the fast-moving train bolts from the tracks leaving no survivors--except him. What's more, he hasn't a single scratch on his body. This puzzles some people, who wonder whether David has been given some remarkable powers like, oh, Superman or Captain Marvel or Batman, and indeed we are soon thrust into the milieu of comic books when David meets Elijah Price (Samuel L. Jackson). Price, who sells expensive comic book covers and has a deep reverence for the uncorrupted art of illustration, is fascinated by David because they are so physically different. Price, victim of scores of broken bones dating back even to his embyonic state, believes that the unbreakable David is his polar opposite and quickly becomes Bhavagan to David's Arjuna.

"Unbreakable" is unmistakably a Night Shyamalan film, based in part on the young director's own life. Coming from a family that includes twelve doctors, Shyamalan graduated from college with honors and received scholarships to medical school. Despite his environment, Shyamalan knew who he was, and doctor he wasn't. Obsessed with making films, he shucked family pressure, relinquishing the hypodermic and prescription pad for the director's chair. "Unbreakable" is inspired by his own life, which Shyamalan translates into art, contrasting a guy who knows exactly who he is with someone who is spiritually lost. As the comic book connoisseur is at first shrugged off by the melancholy security guard, then embraced only to be rebuffed once again by Dunn, we in the audience are kept suspended, sometimes even wondering: What's going on? Where is this story heading? While many of us were intrigued by "The Sixth Sense," which had a tighter story line and a knock-your-socks-off outcome that eluded us until we were slammed back in our seats by The Big Payoff, "Unbreakable" by contrast seems jagged, unedited, rough- around-the-edges while the characters plod ever so slowly through their paces. The movie has the foggy look so fashionable in the films of Ingmar Bergman such as "The Seventh Seal," even some domestic scenes that could have come from the Swedish director's "Scenes from a Marriage"-- the sorts of vistas that could tip a film from art into pretension, as Woody Allen showed us in his satiric "Shadows and Fog."

Not that there's anything wrong with slow and misty...Recent offerings such as Terence Davies' "The House of Mirth" based on an Edith Wharton story and Jane Campion's "The Portrait of Lady," from the Henry James novel, lumber on, bleak and dreary. But what is monotonous on the surface is redeemed by sparkling dialogue, heaped with wit and satiric power. The banal talk in "Unbreakable" cannot sustain the weight of Shyamalan's movie, making this one a disappointing follow-up to his superior work of last year.

What's more, while we can understand what David saw in the beautiful Audrey, we may have difficulty comprehending what a centered, intelligent woman who delivers sparkling psychological insights to her patients while on the job as a physical therapist sees in David Dunn. Willis and Penn simply don't feel like a couple, not even when they try to renew their relationship by having a date in a swank Philadelphia drinking emporium.

Samuel L. Jackson turns in a razor-sharp performance, even when trapped in a wheelchair, large pins sticking out of his legs. He does make us wonder throughout just what his interest is in the disconsolate security guard, since he does not come off like Will Smith's god-like Bagger Vance in the Redford movie. "Unbreakable" could appeal to comic-book fans, though the picture does not have the qualities of an animation at all, but fans of Willis and Jackson may well be disappointed by its foggy, pretentiousness texture.