Wagner's Ring Cycle is a sprawling opera that stretches for hours.

Look closely at center stage a woman in this little box can make all the difference between a smooth performance and an unruly one.

Her job: Opera prompter.

“I give the advance words and I give them an advance notice,” Carol Isaac said.

“The prompter has to be a highly trained musician. She can hear if they made a wrong entrance she'll do something like that and ask him to hold up a second wait a minute wait a minute you have two more measures before you come in okay now. That's why the singers love the prompter because they put them back on track,” MET Opera Archives Director Peter Clark said.

Before each performance Carol Isaac climbs into her little box from the orchestra pit and raises her seat just enough to be seen by the singers but not the audience.

“It's really really small in there - yes it's small but I'm used to it,” Isaac said.

The Met stages more than 200 performances a season with eight different prompters leading the singers in Italian, French, Czech, Russian and German.

“The piece that we're doing now from Wagner's ring is almost 6 hours long and we might have the tendency to sing the words from 30 minutes ago me and Carole down in the box is like no, it's this,” Opera singer Eric Owens said.

Isaac grew up in Canada playing the piano and studying music.

She was a successful accompanist, vocal coach and prompter when she moved to New York for this role more than a decade ago.

“It's great to get a set of ears that you trust and then to have to have that person be there on stage with you it's like she's lifting me up,” Owens said.

“It's actually my job, my pleasure to do it because what happens when I'm in the box, I hear great singing. It’s incredible. The best seat in the house,” said Isaac.

It really makes you think: it would be great if in every situation you got the next line in every language with the right note at the right time.

Sure the storyline of many operas can be confusing but at least now when you see this at the end of any performance you'll know why.

“I have to stay in the box for the curtain calls so they come by and they say thank you,” said Isaac.

And for that they need no prompting.