As they have every spring since 1979, a year after Affirmed became the 11th horse to win the Triple Crown, oddsmakers and horsemen throughout the country have scoured this year's crop of 3-year-olds for the next truly great thoroughbred.

The field has been narrowed to 20 set to run in the 138th Kentucky Derby on Saturday, May 5 at Churchill Downs.

One of the deepest fields in years 10 to 12 horses are believed to have a legitimate shot at winning shows why the Derby remains such a beloved event: A longtime favorite enters the race shrouded in doubt, while the ultimate newcomer has everyone swooning.

With 18 other horses some enigmatic, others workmanlike in the chase, there's sure to be intrigue.

Here are five story lines to watch:

Can Bodemeister continue his rise?

There hasn't been a Kentucky Derby winner who didn't race as a 2-year-old since 1882. Only 17 horses even have attempted it in the last 20 years, with Strodes Creek (second in 1994) and Curlin (third in 2007) coming the closest. But Bodemeister, named after trainer Bob Baffert's son, is the likely favorite heading into just his fifth race.

He ran past the Arkansas Derby field, winning by 91/2 lengths. Though there's concern about his maturity and conditioning as would be the case for any lightly raced colt Bodemeister has captured the imagination of those seeking the next Triple Crown winner. He's that fast. Baffert has won the Kentucky Derby three times, most recently with War Emblem in 2002, and won the Preakness in each of those years. Owned by Zayat Stables, Bodemeister has been working at Churchill Downs since his win in Arkansas.

"He likes this track," Baffert said. "He just skipped over it. He is very fluid when he just picks it up and floats over the ground."

Will Union Rags recover from a Florida Derby letdown?

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Bodemeister's rise tops Kentucky Derby storylines