Though it is in many respects just another odd couple road movie, "Rain Man" evolves into a very special film, largely because it is about something. That alone distinguishes it from most movie fare these days, but add to that an uncompromising look at love, tolerance and a sensitive understanding of mental disabilities and you have the potential for something great.We are not talking about a mawkish, glossy soap opera, however.

The direct approach of the director, Barry Levinson ("Good Morning, Vietnam," "The Natural," "Tin Men," "Diner"), and the superlative performances of his stars, Dustin Hoffman and Tom Cruise, help the material here rise far above melodrama, making "Rain Man" a knockout film.

"Rain Man" is the story of Charlie Babbitt (Cruise), a lonely, inward, bitter young man who ran away from home as a teenager and has not been in touch with his widowed father since.

When news of his father's death reaches him, Charlie is seemingly unemotional, but he heads for his home in Cincinnati anyway, hoping that the old man might have remembered him in his will. Charlie is a hustler whose shady car business desperately needs $80,000 to stay afloat.

He is not prepared for what he discovers, however. He has an older brother, an austistic savant named Raymond (Hoffman) who has been in an institution for more than two decades. And Raymond has inherited $3 million from their father's estate.

Learning that Raymond doesn't understand the concept of money just makes Charlie all the more anxious to go after it. So he "kidnaps" his brother, hits the road for Los Angeles and soon learns that autism requires 24-hour care, and he doesn't have the patience to deal with it.

Charlie soon learns the necessary patience, however, and it's not hard to figure out that before the movie is over Charlie will learn to love and cherish his brother and lose his mercenary tendencies.

In some ways "Rain Man" takes the easy road, such as when Charlie discovers Raymond's amazing abilities of memory: He teaches him to count cards, takes him to Vegas and wins just enough money to rid himself of his money problems.

But in more important ways, the script is uncompromising. Though Charlie changes throughout the film and learns much about himself, his brother and about tolerance and love, Raymond never changes. He is just as uncommunicative and frustratingly simple when the film ends as when it begins.

What's more, the movie is frequently very funny, but never at the expense of the characters.

This is as it should be, but it's unusual for Hollywood to take the hard road, and it must have presented untold challenges to Levinson, Cruise and especially Hoffman.

While Cruise goes on an emotional rollercoaster - and gives the finest performance of his career - Hoffman must hold it all in. To do this, Hoffman cocks his head to one side like a bird, stares blankly, never makes eye contact with anyone and gives his performance from within. Raymond is very childlike, rigid in his routine and when that routine is interrupted he recites the Abbott & Costello "Who's On First?" routine over and over again. And he cannot carry on a normal conversation. Hoffman delivers an amazing performance, one that will have you believing you are watching an austistic person, not Dustin Hoffman in performance.

The rest of the cast, made up of unknowns, is also quite good, but special mention should go to Valeria Golino as Charlie's girlfriend, a fiery, charged-up and charming performance.

Come Oscar nomination time, don't be surprised to see Hoffman, Cruise and Levinson as front-runners, along with director of photography John Seale and screenwriters Ronald Bass and Barry Morrow.

"Rain Man" is rated R for considerable profanity from Cruise's character, and a sex scene that is comic in nature, with some very brief nudity.