An inspirational story and riveting performances by Haley Joel Osment, Helen Hunt, and Kevin Spacey fail to save Pay It Forward from being sabotaged by its dismal ending. Still, this unusual drama is worth seeing because of its three amazing stars.

Osment, as a youngster trying to change the world, stole my heart just the way he did in The Sixth Sense. Hunt, much more serious here than in her Oscar-winning turn for As Good As It Gets, is immensely sympathetic as Osment’s alcoholic mother. And Spacey, who won an Academy Award for a flashier role as the disgruntled husband in American Beauty, surprised me by his low-key, sensitive portrayal of a repressed social studies teacher whose emotional scars are as severe as his physical disfigurement.

"I guess you’ve never seen a new teacher before," Mr. Simonet (Spacey) tells his 7^th grade students who gasp at the scars on his face when he turns from the chalkboard. He has written an assignment there --- one he always uses at the beginning of the year. "Think of an idea to change the world and put it into action," he challenges the students, promising extra credit for anyone who takes him up on it.

Obviously, Simonet doesn’t expect any response to this assignment. But Trevor (Osment) sees lots of things about the world that could be improved, so he comes up with the concept of "paying favors forward." Standing before the class, the motivated student explains, "It has to be something that really helps people, something they can’t do by themselves, and if I do it for them, they do it for three other people."

There’s an important reason why Trevor takes this assignment to heart. His own life desperately needs fixing. Even though he’s only eleven years old, he has to fend for himself most of the time. His mother (Hunt) works two jobs just to make ends meet. By day, she’s a change girl in a Las Vegas casino (her nails display little golden dollar signs!); at night, she waits tables in a strip club. Deserted by her husband (Jon Bon Jovi), she struggles with a serious drinking problem. With the help of a terrific make-up job, Hunt projects the most believable "hung over" look since Susan Hayward in I’ll Cry Tomorrow. Haggard and bleary-eyed, the guilt-ridden mom hides booze from her concerned son, who pours it out when he finds her liquor bottles.

Deciding to put his social studies assignment into action, Trevor picks a homeless person (James Caviezel) as the first person to help. He invites the man home, feeds him, and gives him a place to sleep. Next, Trevor sets his sights on his mom and Simonet. In the film’s best scenes, the lad’s attempts to start a romance between his mother and teacher lead to amusing misunderstandings. Osment is delightful as he secretly sets up a candle-lit dinner for the two unsuspecting adults.

Does Trevor’s "pay it forward" philosophy work? Enough to get media coverage by a reporter (Jay Mohr), the recipient of a mysterious good deed. But some of Trevor’s efforts backfire with disastrous results. This movie is not a comedy, in spite of its light-hearted moments. Changing the world for the better can be serious business. Sadly, the way Pay It Forward ends suggests it’s too dangerous to try.

(Released by Warner Bros. and rated "PG-13" for mature thematic elements including substance abuse, sexual situations, language, and brief violence.)