MIAMI -- The most anticipated subplot of Super Bowl LIV will be on the sidelines.
Andy Reid and Kyle Shanahan are two elite offensive head coaches performing at their peaks and looking to confuse the hell out of every defender who gets in the game.
Reid has proved to be a master play designer with the Kansas City Chiefs, watching countless hours of film to find an edge. Shanahan is the slick playcaller for the San Francisco 49ers who can catch fire in a hurry because he sees what's coming.
Anything less than a combined 60 points this Sunday will be a downer.
To better understand their offensive genius, ESPN talked to those who have shared meeting rooms and headsets with Shanahan and Reid.
An index card and a wink
Every Tuesday, Andy Reid draws creative plays on 5-by-7 index cards and hands them to the Chiefs' quarterbacks to review. The group picks a favorite or two, and they try them out in offensive install that week.
The more bizarre the formations, the better.
"There are a couple where literally it's like three guys in motion, one coming here, one there, faking the pitch, tossing it around and throwing it back to Patrick [Mahomes] -- it's like, 'what are we doing?'" backup quarterback Chad Henne said. "Who sits here and finds these? He watches so much film, even '90s stuff."
Reid always finds a way to get at least one crazy play into the game plan, and when it works, Henne looks for a classic Reid reaction.
"He just winks and laughs," Henne said. "Because he knows how special Patrick is [executing those plays]. ... And we usually say, 'Yeah, that's pretty good, Coach.'"
The 2014 Cleveland Browns coaching staff was ready for its first practice of organized team activities, and Shanahan -- the new offensive coordinator hired by Mike Pettine in February of that year -- was breaking down 9-on-7 situations and the inside running game.
Typically, staffs have 90 minutes before the players are ready to hit the field, and they have to get through 10 running plays, which most coordinators rip through with plenty of time.
Shanahan needed the full 90 minutes and fell a play short of finishing.
"That right there told you how detailed the guy is," said Brian Angelichio, the former Browns tight ends coach who's now with the Carolina Panthers. "That was the first time we were all together. Rewinding it over and over -- landmarks, combination blocks, the speed and tempo, how he wanted it all to look. Right there you knew, 'OK, he knows the importance of all this.'"
Shanahan needed the time because his scheme is complex. The 49ers motion and shift at dizzying levels, which tight end George Kittle says requires a ton of memorization and nuance but maximizes potential.
Kittle is known for his ability to block defensive linemen, but he points out that Shanahan emboldens him with his scheme.
"You don't just line up a tight end with a 6-foot-6 defensive end and say 'Block this guy,'" Kittle said. "So he sets them up with different motions, pin blocks, pull blocks -- making my life a lot easier."
Text barrage at dinner time
Brad Childress was out at dinner most Friday nights when he'd get the predictable text.
Reid always group-texted Childress and then-offensive coordinator Matt Nagy with two different 15-play opening scripts for Sunday's game. He wanted the Chiefs assistants to pick their favorites, and they'd meet at 7 a.m. Saturday to talk about them.
"Then sometimes he'd say, 'I'll put on another 15, I'm feeling it,'" said Childress, Reid's former offensive coordinator in Philadelphia and a former assistant in Kansas City. "So he would send nearly 50 plays on a Friday night from his office."
Reid's preparation is revered, and it comes from experience. Reid learned the detailed approach from playcalling great Mike Holmgren in Green Bay. Holmgren learned from Bill Walsh.
But Childress also appreciates Reid's willingness to set an early-game tone with those play scripts. He remembers one 10-game stretch in Philadelphia when Reid insisted on throwing a "complete bomb" early in each of those games.
"We said, 'Coach, can we really do that each time?''' Childress said. "And he said, 'Why wouldn't we?' He wasn't afraid to dial it up."
Like an ace pitcher working through six innings of no-hit baseball, Shanahan should be left alone when he's feeling it.
Offensive assistant Miles Austin can tell when Shanahan is cooking because the plays come out rapid-fire style, and he's already looking three plays ahead.
"You can feel it and the stadium feels it," adds passing game coordinator Mike LaFleur, who has been with Shanahan since 2014 in Cleveland.
The common theme with Shahanan is foresight. He's not calling plays; he's bending a game to his frequency over the course of three hours.
And he loves to predict what's coming. Before a game with the Los Angeles Chargers in 2018, Shanahan told quarterback C.J. Beathard he would have a touchdown if he looked off the safety on a specific play. That Sunday, Beathard looked off, and tight end George Kittle went 82 yards for the score.
A clip from the NFC Championship Game went viral as a miked up Shanahan successfully predicted to an official that Kittle would be held on a 5-yard out route:
Players laughed about that clip but were hardly surprised. "He's the king of calling his shots," fullback Kyle Juszczyk said.
Defensive backs coach Joe Woods says Shanahan understands what a defense wants to do better than any playcaller he's been around in 15 years. This comes from pedigree: Father and coaching great Mike Shanahan used to tell Kyle that knowing defenses is more vital to offensive success than his side of the ball.
Enter the playcall room at your own risk
Reid and his coaches get together at least once a week and attack the white board with far-reaching play ideas.
"No such thing as a bad idea," offensive coordinator Eric Bieniemy said. "Just as long as no one gets their feelings hurt. Some are better than others."
Nothing is personal, but Reid is hard to top in this room because he's constantly digging for new plays to curate the Chiefs vibe. It's the equivalent to a hip-hop producer digging in crates for old jazz samples.
One famous example is Reid finding the All-Go Special Halfback Seam play from North Dakota State tape, then scoring a Kareem Hunt touchdown with it in 2017.
But Reid is going back decades to spin the oldies.
"He can come up with something from Montana State and you'll ask him, 'Where did that come from?'" Childress said. "And he'll say, 'I got it from the Big Sky Conference.'"
No numbers allowed
Brian Hoyer has played for eight NFL teams since 2009, and a Shanahan offense makes the quarterback's job most difficult for one fundamental reason.
"He's the only OC I've had where he doesn't have a numbered call sheet," Hoyer, who played for Shanahan in Cleveland and San Francisco, explained. "In certain schemes, they would say, 'wristband No. 78.' But Kyle doesn't have that. It always drove me nuts because his offense is wordy, but he says he can't put it numerically because he needs to watch the defense, then call the next play."
Shanahan isn't limiting himself to a down and distance. It's all about the defense's vulnerabilities. That proved true when he called a trap play on third-and-8 in the NFC title game that Raheem Mostert turned into a 36-yard score.
"With Kyle, he almost doesn't care -- he's simply seeing how the defense is reacting in the moment," Hoyer said. "It's a very unique thing."