It was Amber White’s second day as a stage manager on “Hamilton,” and Lin-Manuel Miranda, the show’s creator and star, was sick.

Viewers who buy their tickets months in advance are never happy to hear about a substitution. This was Broadway’s hottest show, based on a brick of a book by historian Ron Chernow, a fresh depiction of the New Yorker who fathered the American banking system, endured a sex scandal, and died in a duel. This was the first time that Miranda or Javier Muñoz, who plays the role on Sundays, didn’t appear as the title character. The role went to Jon Rua, the understudy, making his debut as America’s ten-dollar founding father.

White and the production team called an emergency rehearsal — 30 minutes long — for which the cast came to the theater. And then the show went on: “flawlessly,” White said, thanks to Rua but also the professionalism of the rest of the cast and crew.

White, 36, is one of the crew members in the room where it happens for eight shows a week, critical to the musical’s success but largely unseen.

Stage managers, three of whom work at a time on “Hamilton,” are the guardians and protectors of the show and the cast — “a cross between a flight attendant and a mom,” White says — who tend to the mental and psychological well-being of the actors.

They are also often with the show long-term, from pre-production meetings on design and concept through to rehearsals, previews and performances, taking care of the practicalities of scheduling and organization. And, always, troubleshooting.

During a recent production of “Hamilton,” an ensemble member hurt his neck with about 35 minutes left in the show.

Coming off stage, squeezing past barrels of prop rifles and shelves of neatly stored mugs, he went to the stage managers’ office to find White. The actor said he couldn’t go back on.

Quickly, White paged one of the swings — an understudy ready to fill in for multiple roles at a moment’s notice — upstairs in his dressing room. She and the other stage managers coordinated the switch, getting the swing into costume and microphone and on stage in time for his new character’s next appearance. The hurt actor went home.

The show went on. The audience never noticed. Crisis averted.

5. Okieriete Onaodowan (Hercules Mulligan/James Madison) jumped onstage to applaud a guy for filling in a front row seat.
When the announcer asked an audience member to sit in the empty seat (for the cameras, darling), a man from the middle of the theatre sprinted to the front. As the crowd burst into applause, Onaodowan jumped out from backstage to join in.

6. After Hamilton won the Grammy for Best Musical Theater Album, Lin thrust the trophy into the air and said, “Take pictures!”
And in the most obvious (but still perfect) joke of the night, he yelled, “You’re in the room where it happened, motherf—ers!” before handing the trophy to Anthony Ramos (John Laurens/Philip Hamilton) and saying, “Now take pictures of Anthony with it!”

7. An emotional Anthony Ramos gave his mother some love.
“Yo, ma! This is for you!” he yelled from the stage to where she beamed in the orchestra pit. “From Bushwick to Broadway!”

8. The real Eliza Schuyler Hamilton was in attendance — sort of.
In the song, “Who Lives, Who Dies, Who Tells Your Story,” Eliza sings about founding the first private orphanage in New York City. That organization, Graham Windham, still exists today, and its president (along with some students!) were in attendance. The Hamilton legacy lives on!

Just…. Lin-Manuel’s face when the Grammy crowd cheered so loud at his appearance that his second line couldn’t be heard.