On the stage, singers and dancers perform in front of digital screens that instantly slip into place, each one blazing its own array of vibrant images.

Music blossoms through the theater from the orchestra, playing in full view of the audience from a sheltered enclosure underneath the stage. And though this is a summer night in St. Louis, this dream brings pleasant weather. Everyone enjoys refreshing breezes.

What if that weren’t a dream?

What if it were a plan?

It is a plan — a plan that Muny leaders had planned to unveil Friday night at a gala marking the start of the theater’s centennial season. Because of rain, the big reveal was postponed a day.

Most of the Muny updates will be in place for the theater’s 2019 season. Construction begins in August, right after “Meet Me in St. Louis” closes the 100th season.

Those upgrades won’t come cheap. The Muny is also launching a capital campaign — its first — which comes with a centennial-size goal: $100 million.

“We don’t just say ‘happy birthday,’” observed Steve Jones, chairman of the Muny board. “We say ‘happy birthday and many happy returns.’

“This is happy returns for the next 100 years.”

Muny president and CEO Dennis Reagan points out that for the past 15 or 20 years, all Muny improvements have concentrated on amenities that directly affect the audience.

They include the overhead fans that circulate air during every performance, the fountain and plaza around it, the landscaped upper plaza, larger concession areas and modernized restrooms.

The 2018-19 changes, however, will concentrate on the theater itself — on what artistic director and executive producer Mike Isaacson calls “better magic.”

The big elements:

“Shells” around the stage • The most striking element of the new design, they dramatically define the playing area. Made of glass fiber-reinforced concrete, these structures can be “colored” with light. They also will hide the black towers on either side of the stage, which hold electronics and sound equipment. Both towers will be modernized on the inside.

A new stage • It will have two turntables, tracks to move scenery easily and five lifts to bring objects, or actors, onto the stage from below. “The scariest word in a script is ‘suddenly,’” Isaacson said. “We haven’t had ‘suddenly’; we’ve had 40 feet to cross!” That’s going to change but will involve removing some trees.

New lighting • All LED, the new lights will allow designers to create limitless color variations on the stage and around it. The number of lighting instruments will quadruple, and the stage will accommodate more LED screens. Digital projections are common, Isaacson says: Just look at the visual design of such current shows as “Mean Girls” and “Summer: The Donna Summer Musical.” The last element of the stage redesign, a new overhead light bridge, goes in after the 2019 season.

A new orchestra area • It will place musicians under the stage instead of in a pit. They will be visible to the audience, but they will play in a sheltered, climate-controlled area that’s better for instruments as well as people.

Better breezes • Air ducts hidden in the new shells will distribute air more evenly through the theater.

Then, sometime in late 2020, the redesign will travel backstage to areas most Muny-goers never see: dressing rooms, costume and wig shops, and work areas for scenic construction. The crafts artist, for example, currently works in a corner, making such accessories as hats and jewelry.

The roof will be replaced, and so will the gates. Basically, the whole backstage will be streamlined. The timeline isn’t set, but it will take years.

These changes have long been needed. “The reality is, we produce shows in a place that’s not up to modern standards,” said Sean Smith, director of operations at the Muny. The current, single turntable — a huge innovation when it was installed in 1930 because it made scene changes much faster — is now “less than reliable,” Reagan said. The current light bridge, on which lighting is hung across the stage, is only five years younger.

Isaacson jokes that the Muny does incredible productions, using the very best of mid-20th-century equipment. That’s not quite true, but the reality impressed Joe Mobilia of Fisher Dachs Associates, a theater planning and design firm based in New York.

“What they are doing is impossible,” said Mobilia, who considers the Muny his “second-favorite project” (after the 2000 renovation of Radio City Music Hall in New York). “We spent days on the site and saw the superlative effort the season takes, and they do that year after year.

“The broad mission (now) is to continue the spirit of the place, making upgrades that refresh the building at every level. We are talking about what it will look like now and in 50 years, acknowledging the past yet looking forward. You’ll walk in and see the changes immediately.”

Looking forward

The big project has been in the works for about four years, since the Muny board asked Michael Kaiser — a noted theater consultant who formerly headed the Kennedy Center — to advise a route for the future.

Since then, specialists and contractors of every sort have been brought in to work on the project. Among them is the man who came up with the shells, lead architect Ariel Fausto.

“We needed a design that spoke to (the Muny’s) mission, to the context of Forest Park, to the Muny’s history — and that positioned the Muny for the future,” said Fausto, a partner in New York-based H3 Hardy Collaboration Architecture.

Hence, the shells, which “point you toward the stars. We wanted to evoke the organic aspect of the theater, the way the tree canopy does.”

Ah, yes, the tree canopy.

“The canopy, the way it takes the light and adds to production values — that’s our special sauce,” said Muny production manager Tracy Utzmyers. “We love it.”

The first impulse was to leave all the trees in place and work around them. But “we have a lot of trees,” explained Smith. “So, if we are digging up the whole stage,” there would have to be compromises.

Most of the concern centered on one tree, the enormous oak that stands stage left. It’s thought to be almost 300 years old.

Suffering from disease and listing dangerously, its “twin” on stage right was removed in 2002. The oak at stage left is now in bad shape, too. “The root system has grown into the concrete,” Smith said. “We think the stage itself is holding that tree in place.

“We don’t take the decision lightly, but that tree will come down. But if we plant trees properly, the canopy will be maintained.” Smith and others visited a tree farm near Chicago where they selected seven large trees that will be planted on and around the stage, along with other, smaller trees grown locally.

Oak trees are particularly treasured, Utzmyers said, because their big, flat leaves pick up light beautifully. One day, the old oak’s descendants will be part of that appealing look: Muny workers are already collecting its acorns to plant.

For the community

“This (capital) campaign is going to do an awful lot of brick-and-mortar improvements,” said the campaign chairman, Jim Turley. But, he added, there are other demands as well.

Looking forward, the Muny needs to be able to sustain and expand its many educational programs, to be able to hire top talent, to be able to cope with emergencies and to enjoy an endowment that makes all its efforts sustainable. Not part of the Zoo-Museum District, the theater in Forest Park receives no public money.

To Reagan, it’s essential that the future Muny continues to be as affordable as it is now. “We have seats that cost $15. We have free seats. We give seats away (to social service groups),” he said, noting that the campaign has already made “substantial progress” toward its goal. “The Muny is all about accessibility. That means financial accessibility, too.”

The drive is not aimed only at big givers; it’s a community-wide campaign. “If you can give us $100, that’s amazing — and we will ask you for it,” Isaacson said. “We always want everybody to be part of the Muny, in every way, including money. The Muny belongs to the community.”

With the improvements, it will also assume its historic place in the small community of exceptional American venues, he said. “This is bold,” he said, adding that he thinks theater artists will be impressed along with theatergoers. “Everybody is going to say, ‘I want to be on that stage.’ ‘I want to create for that stage.’ ‘I want to go to St. Louis.’

“When the Muny was built, it was one of the greatest stages in the United States. When we do this, we will be alone in our greatness again.”