Racetrack dreams make beautiful underdog stories—books, movies, TV shows. The plucky little horse who wins millions by a nose. The lifetime bettor who finally scores with his last $2 ticket. The jockey who overcomes hardship and injury to ride a champion. Hollywood even made an overachiever out of Secretariat, one of the most dominant athletes in history. But the reality of racing is darker: What dreams customarily do at the racetrack is die. The plucky little horse is beaten, the bettor goes home broke and the jockey limps away. Nowhere is this more true than at the Kentucky Derby, where nearly 30,000 baby thoroughbreds have been winnowed to 20 3-year-olds in the starting gate—just one of whom will enter the winner's circle.

California Chrome should not have been the one. His inexperienced co-owners, in their first attempt at breeding a racehorse, spent $8,000 on a slow filly and bred her for $2,000 to a stallion who got very tired running anything approaching the 1-mile distance of the Derby. The colt's trainer is 77 and hadn't been to the Derby since a few years after he slept in a rail car from L.A. to Louisville with 1955 winner Swaps. Chrome had won four consecutive prep races but none outside California. Yet late Saturday afternoon, as the 5--2 favorite, he ran far into the lead beneath the twin spires of Churchill Downs and through long shadows past the finish line to win the 140th Derby. "What are the odds?" said one of his co-owners, Steve Coburn, who with partner Perry Martin turned down $6 million for 51% of the chestnut two months ago. "A billion to one?"

California Chrome got his name because of his four white feet and the giant white blaze on his face—in racing parlance, white markings on a horse's coat are called "chrome"—and because he was foaled in California. He is the first horse bred in that state to win America's most important race since 1962. Sherman, all of 5'2½" and 138 pounds, 40 more than he weighed as a teenager, is the oldest trainer to win the Derby. "I've been around a long time," said the former exercise rider after the race. "I'm just the same old Art Sherman, you know, except I won the Kentucky Derby."

Rival trainers had criticized Sherman for bringing Chrome east just five days before the race, and indeed, on the horse's first morning in Kentucky, Sherman had to rouse him from a deep sleep at 5 a.m. to go for a short jog. "I hated to wake him up," said Sherman. "Especially when I realized it was only two in the morning for him."

Jockey Victor Espinoza, 41, who hasn't lost in five races since replacing Alberto Delgado, rode superbly in the Derby, escaping from the number 5 post position to stalk a modest pace. He ran away in the stretch to win by 1¾ lengths while gearing down in the final strides. "This horse is so talented," said Espinoza. "He can do anything." Espinoza's older brother Jose, 44, a jockey who suffered a brain injury in a fall at Saratoga last summer and had turned away from racing entirely, flew in from New York on the morning of the race to watch Victor's win.

Now they go to Baltimore for the May 17 Preakness at Pimlico Race Course, and with each passing day the chorus will rise in support of a run at the first Triple Crown in 36 years. It is still far too early, however, for such talk. As few as two of the 18 horses that California Chrome defeated in the Derby could run at Pimlico, where he is likely to be an overwhelming favorite. But many others will skip the Preakness and lie in wait to ambush the Derby winner on June 7 in the Belmont Stakes. For now the Triple Crown is a possibility and nothing more. But what a story that would be.

PHOTOPHOTOGRAPH BY SIMON BRUTY SPORTS ILLUSTRATEDCOURSE HORSES A few yards after the start, California Chrome (fourth from right) had yet to separate himself. PHOTOPHOTOGRAPH BY BILL FRAKES SPORTS ILLUSTRATEDCHROME STRETCH After making the turn for home, the rags-to-riches chestnut opened up a big lead. PHOTOPHOTOGRAPH BY SIMON BRUTY SPORTS ILLUSTRATEDEASY, RIDER Espinoza went to the whip only twice in cruising to victory by 1¾ lengths.