With the king of opera on stage and the Queen of England in the patron's box, the Royal Opera House at Covent Garden will hold a glittering celebration tonight to mark its rebirth after a long and nearly disastrous period of silence.

The Washington Opera's artistic director, Placido Domingo, will serenade her majesty--and a national television audience in Britain--as the headliner of the long-awaited gala at Covent Garden, famous to Londoners as the place where Henry Higgins first met Eliza Doolittle. The evening will mark two great occasions: the completion of a beautifully refurbished opera house, and the achievement of a balanced budget for it.

There were times during the last 2 1/2 years when nobody here was confident that either goal would be achieved. Since its much-loved neoclassical house was closed for reconstruction in July of 1997, the company has gone through more dramatic twists and turns than a Puccini tragedy.

The board members, primarily blue bloods chosen more for family stature than for talent, did such an egregious job of planning that the resident opera company and its co-tenant, the Royal Ballet, were left with no place to perform during much of the rebuilding period. With costs fixed and almost no ticket income to cover them, the deficit went into a terrifying crescendo.

Four successive chief executives came and went in less than two years. Famous artists threatened to walk out. Both board members and artists seemed to devote much more energy to back-stabbing than to putting the house in order.

And then, virtually in the last act, a heroic figure emerged. Following a fairly common pattern here, the troubled British institution turned to an American to save the day. It was Michael Kaiser, a former board member of the Washington Opera and a man with considerable experience at saving troubled arts houses, including the Alvin Ailey American Dance Theater.

Over the past year, Kaiser has soothed the internecine battles, imposed a regimen of careful planning, and introduced American-style fund-raising that has turned a $32 million deficit into a budget with a (tiny) surplus.

At first meeting, you might not think of the 45-year-old New Yorker as an operatic hero. Universally described as gentle and quiet, Kaiser is so humble that he genuinely seems embarrassed at the gushing coverage he has received from London's normally savage arts correspondents. He practically blushes when reminded of the headline over a Daily Telegraph story about him: "A Miracle at the Garden."

"Yes, they are giving me credit, but I don't deserve the credit," he said the other day from his office high atop the opera house, with the screech of band saws and the fragrance of wet paint still filling the hall. "We have wonderful professionals here, and all I did was tell them to go ahead with the things they knew how to do."

One thing Kaiser took advantage of was London's intense love for dance and music--it is one of the greatest opera cities on Earth--and the widespread consensus that the opera house at Covent Garden should be an institution respected around the world.

The first opera house went up beside the Covent Garden street market in 1728 (with posters touting the first production, John Gay's "The Beggar's Opera"). The current neoclassical gem was constructed in 1858. The Royal Opera has been, in essence, the home field for composers from Handel to Britten.

George Bernard Shaw, an opera fan of the first order, was always amused by the juxtaposition of the titled rich arriving for the opera and the ragged vendors peddling their wares at the market next door. Covent Garden gave him the inspiration--and the opening scene--of his play "Pygmalion," which was to become the musical "My Fair Lady."

In recent years, though, the contrast between the rich folks at the opera and everybody else became a source of severe political tension. By the mid-1990s, Covent Garden was charging up to $200 for a seat to performances that were subsidized by the taxes of working people. Lower-income opera fans could occasionally get a balcony seat for $30 or so, but anyone bearing such a bargain-basement ticket was required to enter the house through a separate door from the toffs.

One of the key goals of the refurbishment was to deal with the inbred elitism of the house. As Kaiser proudly notes, the new opera house at Covent has one set of entrances for box seats and balcony alike. Two small theaters in the house can be used for low-cost student performances. The great 19th-century Floral Hall, which had been reduced to the lowly status of scenery shed, has been restored as an airy, open foyer that also can be used for performance.

Last week, with the end of the turmoil in sight, Kaiser himself suffered a setback when he was forced to announce the last-minute cancellation of one of the five operas scheduled for the repertoire this winter. For avant-garde fans, Gyorgy Ligeti's "La Grand Macabre" would have been one of the highlights of the season. But Kaiser finally decided "the staging was just too complicated to figure out in a brand new theater."

The cancellation will cost about $400,000. But Kaiser calmly reported that he had set up a contingency fund to handle just such problems, without breaking the bank. In any case, canceling the fairly cultish Ligeti certainly made better business sense than the board's first plan, which was to cancel the new production of Verdi's "Falstaff," a sure sellout.

In 1998, when the Royal Opera's situation looked truly dire, the company reached across the Atlantic and called in Domingo to perform a concert version of Wagner's "Parsifal." That proved to be an artistic and financial triumph for the house. So it was only natural that Domingo would be recruited to sing tonight for the queen at the newest grand opening of London's oldest and best-known opera house.

CAPTION: The refurbished Royal Opera House will reopen with a gala tonight, with Placido Domingo singing.

CAPTION: The Vilar Floral Hall, a restored Victorian glass house at the Royal Opera House, is named after American philanthropist Alberto Vilar.