Audience will enjoy cracking ‘Source Code’

You probably have a friend who can't keep his mouth shut about the cool movie he's just seen, the one with the interesting twist.

You know the guy - he ruined "The Usual Suspects" for you and "The Sixth Sense."

He may even be a movie critic.

In any case, you need to stay away from that guy for a few days if you want to see "Source Code."

It's built around an intriguing sci-fi idea, but you're better off not knowing what that idea is.

For "Source Code" to work, you need to experience the movie from the perspective of its dumbfounded central character (Jake Gyllenhaal), who wakes up on a Chicago train, apparently in another man's body.

He has no idea who/where he is, but other people seem to know him well - especially the foxy brunette (Michelle Monaghan) who's seated opposite him.

What gives? The man's confusion wanes as disembodied voices (Jeffrey Wright, Vera Farmiga) slowly dole out the details of his situation. His desperation, though, only increases.

"Source Code" finds a way to stretch out the man's frenzied search for clues and to repeat it - he has a short time to find answers but several chances to get it right.

The film has the same sure-handed management of fractured chronology as Christopher Nolan's "Inception" and "Memento," but with the propulsion of a much more accessible Hollywood thriller.

It's a good vehicle for Gyllenhaal, who takes a much-needed break from serious fare - fighting the Gulf War, being tragically in love with a cowboy or a girl with a terminal disease.

"Source Code" has a lot going for it, but it does not have an ending. At least not one with any sort of integrity - the same problem that plagued "The Adjustment Bureau" and "Limitless."

Part of what makes the hidden premise of "Source Code" so intriguing are the elements of melancholy and loss woven into it. Had those attributes been allowed to express themselves fully in the final reel, "Source Code" could have been a real keeper.

Melancholy and loss, however, are two words that will not survive many Hollywood story meetings, and they did not survive this one, evidently.