"The First Saturday in May" is a slick piece of commercial documentary following six thoroughbred trainers as they approach that festival of horseflesh called the Kentucky Derby, with hopes aflame. It's hardly a muckraking piece, but more a celebration of racing at the high end and the extremely prosperous folks who play it.

You can almost discern its flaw from the description: Six is about five too many "heroes" for any story, and filmmaker brothers Brad and John Hennegan keep it moving ahead at the expense of depth or detail. I'm not sure what a trainer does, even after 97 minutes, and the trainers remain ciphers, each with a distinguishing tick.

Frank Amonte, for example, is a city kid whose New York accent suggests a scrapper off the streets. Dan Hendricks is the plucky paraplegic who won't let a wheelchair-imprisoning accident hold him back. Bob Holthus has an old boy's Southern grace and charm, and on and on.

The horses get even shorter shrift -- we never feel their personalities or quirks -- even though the Hennegans do deliver spectacular racing and backstage footage of the sport of kings.

Because it builds toward the most famous race and the most famous horse (Barbaro) in recent times, you know exactly how it's going to end, so the suspense is somewhat muted. It's pretty much for people who know the game well and want their perceptions massaged, not challenged.