But that’s not the main plot of this episode. There’s a $2.2-million Pick Six carryover at Santa Anita Park. The Pick Six requires gamblers to predict the winners of six consecutive races. It’s the most lucrative wager in horse racing, and the most difficult. So difficult that, many days, no one hits it. When that happens, 75% of the money wagered is rolled over into the next day’s Pick Six pool.

As the show begins, gangster Ace Bernstein (Dustin Hoffman) is getting out of a minimum-security prison after serving a three-year sentence. He gets into the back of a car driven by flunky Gus Demitriou, and tells him, “You own the horse.” Whatever Ace did, it earned him a ban from the racetrack. From now on, Gus will be his front.

If you haven’t spent any time at the racetrack, I’m here to decode "Luck" for you. I’m the author of the book "Horseplayers: Life at the Track ," so I’ll be explaining how to bet the Pick Six, the difference between a claimer and a stakes horse, and why trainers don’t want their first-time starters on the rail.

They’re in the grandstand every afternoon, carrying well-penciled, well-folded copies of the Daily Racing Form, the statistics-crammed newspaper indispensable to every handicapper. They live in studio apartments or, when they’re really hard up, motels. They drive cabs to raise betting money. Their St. Vincent de Paul wardrobes mark them as guys who’ll bet $200 on a horse, but won’t spend $20 on a pair of pants. They’re willing to sacrifice fashion, jobs, friendships and marriages because they know that one day they’ll hit that life-changing bet, the one that will give them the means to bet even more money.

If you’ve spent any time at a racetrack, you’ve seen Marcus, Renzo, Jerry and Lonnie, the four luckiest characters on the premiere episode of HBO’s horse racing series, "Luck" (which sneak-previewed in December and aired again Sunday night).

The Pick Six is also the most expensive wager. The odds of hitting one cold -- by picking just one horse in each race -- are up to a million to one. To help your chances, you have to bet several horses in each race. That adds up, so Marcus, Renzo, Jerry and Lonnie pool their money to buy a ticket with a better chance of winning.

(Walter Smith, a trainer played by Nick Nolte, is also filling out a Pick Six ticket. But Nolte is out to make an even bigger score. His exercise rider works out a horse in “23 and change” -- a quarter-mile in just over 23 seconds. Afterward, jockey agent Joey Rathburn, played by Richard Kind, swears he just witnessed a “Derby work.” The horse, Gett'nup Morning, looks talented enough to run in the Kentucky Derby.)

Jerry (Jason Gedrick), a talented handicapper, shows up at the track declaring “I’m tapped out” -- he lost all his betting money in a poker game. But he brings a napkin on which he’s written the day’s picks.

“You singled in the fourth,” Marcus observes.

In the fourth race, Jerry picked one horse -- Mon Gateau. Mon Gateau is 12-1, hasn’t run in two years, his workouts are slow, and he’s ridden by Leon Micheaux, a Cajun apprentice jockey, known as a “bug” because an asterisk appears next to his weight in the Racing Form, indicating he carries a lesser load than more experienced jockeys.

But Jerry believes in Mon Gateau’s trainer, Turo Escalante. Plus, singling a longshot is a shrewd strategy. As Marcus points out, “it’ll knock out three-quarters of the gamblers” who didn’t use Mon Gateau on their tickets. And the boys can afford to play more horses in races where they don’t have a strong opinion. They buy an $864 ticket, using every horse in the final race, so they’re guaranteed to win if they get that far.

To raise his share, Jerry approaches Kagle, a security guard who lends money to desperate gamblers at 3% a week. Kagle gives Jerry the money in exchange for his picks. When Marcus finds out, he’s furious. If Kagle plays their numbers, there will be two winning tickets instead of one, cutting their winnings in half.

In the paddock, trainer Escalante tells Leon -- whom he calls Pinhead -- to stay away from the rail.

“Get him wide,” Escalante orders. “Don’t get him ... stuck.”

Leon gets him stuck. Down the stretch, Mon Gateau is boxed in on the rail, trapped behind a horse in front and a horse to his outside. The Pick Six syndicate just watches in grim silence. With $2.2 million on the line, you’re too nervous to cheer.

Leon finds a hole, and Mon Gateau wins by a neck. Afterward, we see Escalante cashing tickets for $13,200 and $26,400 -- he bet a total of three grand on his horse.

Thinking Jerry was foolish to single Mon Gateau, Kagle didn’t bet the Pick Six. So he approaches the broken-down horseplayers with another money-making proposition. If they win they’ll have to fill out IRS forms, required when a bet pays off at odds of more than 300-1. Kagle offers to cash the ticket “for a fee,” so the government can’t seize any back taxes these fringe-dwellers may owe.

The monitors display the “will pays” for the last race, in which the boys bet every horse. If the favorite wins, the Pick Six will pay only $42,000, since so many other gamblers played him. If a long shot wins, the payoff will be $2.6 million. Coming down the stretch, the long odds No. 8 horse is leading, but he pulls up with a broken leg! No worries. Another long shot swoops toward the finish, and the gang owns a multimillion-dollar ticket.

The grounds crew props a portable green screen on the track between the injured horse and the grandstand … so fans can’t see the veterinarian inject a lethal drug into the animal.

In the racetrack offices, an executive is alerting tellers to call him when the big winners step forward. He wants this story on the 6 o’clock news. The hosts of the on-track TV show wait with a giant $2.6-million check. But the boys aren’t coming forward. Marcus, who is holding the ticket, decides to cash it the next day -- after getting this IRS issue figured out.

What did you think of "Luck"?

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-- Edward McClelland

twitter.com/tedmcclelland

Photo: Ian Hart, Ritchie Coster, Kevin Dunn, Jason Gedrick in "Luck." Photo: Gusmano Cesaretti / HBO