By Rustin Dodd

McClatchy-Tribune

It is the soundtrack of a postseason three decades in the making -- equal parts hype song and celebratory hymn. It plays inside the raucous stadium, and in the champagne-soaked clubhouse after the big victories. But before we get to the one-hit wonder that was blaring over another Royals party on Sunday night, you should know its origin story, how the playoff anthem came from the genius and warped mind of a 25-year-old left-hander from central California.

When Danny Duffy was a high school senior in Lompoc, the school would play the song "We Ready" before its basketball games. It was a minor hit from a little known rapper named Archie Eversole, the chorus anthemic and infectious, borrowing from Steam's "Na Na Hey Hey Kiss Him Goodbye." Duffy always loved it, though, the way it made the student section at Lompoc go crazy before a big game.

So in the late summer months, as the Royals pushed for their first postseason birth in 29 years, Duffy cued up the song in the clubhouse, looking for a similar effect.

"It came to me like a month ago," Duffy said, as the song echoed off the plastic-covered walls following a sweep of the Angels in the American League Division Series. "I was like, 'Dude, we need to get it crunk in here. We need to get it hyped.' "

Moments later, Duffy clutched a bottle of champagne and slipped out of the clubhouse to find his family in the foyer outside. The chorus began to play again.

"We ready ... we ready ... we ready ... for y'all!"

"It kind of stuck in our clubhouse," center fielder Lorenzo Cain said, "we're just running with it."

After four straight postseason victories -- and three champagne toasts -- over the course of 10 days, the Royals do appear ready for just about anything.

For the first time since 1985, the Royals are headed to the American League Championship Series. And they are doing it their way, with a brand of throwback baseball that is heavy on breakneck speed, outstanding outfield defense and a joyous energy that can only be described like this:

"Everybody loves each other," said designated hitter Billy Butler. "This is truly the group of camaraderie."

On Friday night, the Royals will face the Baltimore Orioles in game one at 7:07 p.m. at Camden Yards, the unbridled joy set to be released in another series, in another town. The country is learning about what is brewing in Kansas City.

"Momentum is through the roof right now," Cain said.

Here is an example: Just a few hours earlier on Sunday, Cain had hit the grass twice in the fourth inning for back-to-back run-saving catches as the Angels attempted to mount a charge.

The first came against Albert Pujols, a full-out dive that inspired third baseman Mike Moustakas to tip his cap in salute. But moments later, there came another liner into shallow center. Cain charged in, completed the sliding catch and promptly celebrated with a flurry of screams and flexes on his way back to the dugout.

Back on the infield grass, starter James Shields was lifting his cap as far into the air as he could reach.

"The energy is just the biggest thing," Cain said, "to fight the way we are right now, it doesn't get any better than this. But we got to continue to fight; don't lose focus, and understand that our main goal is to get to the World Series and win it."

October, of course, is the time for grand baseball narratives, the month in which every series victory is reason enough to break out the champagne and every successful team speaks of the merits of clubhouse chemistry.

But as outfielder Jarrod Dyson stood in the clubhouse on Sunday night, the narrative did not feel force-fed or artificial. Here was a former 50th-round pick from the deep-South town of McComb, Miss., a cackling speedster with the word "Zoom" shaved into one side of his head and a lighting bolt in the other. Nearly 30 minutes earlier, Dyson had broken out a series of backflips on the infield grass as the Royals celebrated the sweep.

"I'm the Energizer battery," Dyson said. "So I got to stay energized for the boys. Any time I'm not talking, they think I'm down or they think something is wrong with me. So I got to keep them live and keep them up in here."

As Dyson looked forward to the ALCS, the familiar chorus was reverberating through the Royals clubhouse again.

"We ready ... we ready ... we ready ... for y'all!"

The anthem for a Kansas City playoff run emerged from the Atlanta rap scene in 2002, the same year Royals general manager Dayton Moore and manager Ned Yost were helping the Atlanta Braves to another division title. That same year, the Royals lost 100 games for the first time, ushering in the darkest stretch in franchise history.

Now there is light -- and an ample supply of fun.