Here’s a story for all the secretaries, assistants, pack rats, and anyone who has ever put something away under the assumption that it will never be needed again – only to search frantically for it later. When London’s Royal Ballet began working on a new production of Sir Frederick Ashton’s “Sylvia,” the matter of the costumes presented a challenge. The costumes themselves had been lost or discarded after the ballet was last performed in 1965. And by all evidence, the records of the designs were missing, too.

“We had a lot of photographic evidence, but it was black and white,” the Royal’s Christopher Newton, who staged the ballet, said. But when Mr. Newton described the look of the costumes to the company’s archivists, one of them knew it sounded familiar. After rummaging around, all of the original costume designs were found in a mislabeled file at the Royal Opera. “When the Royal Opera House was redeveloped, everything had to be moved to warehouses, and it got shuffled around,” Mr. Newton said. “The designs gave us all the original colorways.”

Those costumes, and much more, will soon be onstage in New York. American Ballet Theatre, which co-produced the work, is presenting a run of “Sylvia” this weekend (June 3 to 6), then again the following week (June 13 to 15).

If you don’t know the story of “Sylvia,” here’s a tip: Skip the plot descriptions of the older productions. They’re detailed and confusing. The actual story is pretty straightforward. The shepherd Aminta is in love with the beautiful nymph Sylvia – who is not interested. When she is captured by a sinister hunter, Eros intervenes: Sylvia escapes and falls in love with Aminta. Everyone lives happily ever after.

As plots go, it’s maybe not the most compelling, but what this ballet does have going for it is the dancing, especially that of the ballerina. “She’s onstage about 85% of the time. It gives her a wonderful opportunity to show different aspects,” Mr. Newton said. “She’s a huntress. She falls in love, gets abducted. She becomes rather mournful and has to use some womanly wiles to escape. Then she becomes a grand ballerina.”

Not only that, but the score by Leo Delibes is not to be missed. “It’s beautifully written. It’s one of the earliest ballet scores that uses leitmotiv to introduce the characters,” Mr. Newton said. “You really can’t go wrong with it.”

The Royal Ballet revived “Sylvia” last year for the Ashton centennial celebration. Mr. Newton, who was in the ballet as a student and a company member, drew from memory and film footage in resetting the ballet. He also relied on conversations he’d had with Ashton about how the ballet might be improved.

“When I worked with Sir Fred in reviving ‘Ondine,’ we had some talks about redoing ‘Sylvia.’ I took into consideration all the things we talked about,” he said. “He was concerned about Act II, that it didn’t resolve itself.”

On the list of improvements was the removal of two numbers that slowed down the story. According to Mr. Newton, that included a number of divertissements from Act III, which Ashton had interpolated from “La Source,” and pas de cinque for the gods. “There is a slight change in the order, but that just allows Sylvia and Aminta to have a rest,” he said.

When the Royal Ballet presented this ballet during its season, the work unfolded over three acts. But ABT preferred to present it in two acts in order to dispense with the second intermission. (And I, for one, applaud that decision.) There is no reduction in music or dancing; a new set design allowed the last two acts to be presented seamlessly. “We redesigned Act Two so it can have a quick change into Act III,” Mr. Newton said. Which was all well and good anyway: “We didn’t have the designs for the scenery from Act II.”

As for the choreography, Mr. Newton – who retired as the company’s ballet master in 2001 but came out of retirement to stage this ballet – drew from his own experiences in the ballet as a student and company member. He danced as one of the four trumpeters, one of the summer couples, and Jason. But he was most fortunate to have a film of the ballet. “I had a very veiled film from about 1965. It was a film with music added in afterwards,” he said.

Which made matching the steps with the music difficult, but not impossible: “Ashton is a very logical choreographer.”

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I’m ill – and what I’ve got is Vishneva Fever! The Kirov Ballet’s Diana Vishneva is dancing as a guest artist with ABT this season, and in her performance of “Don Quixote” last week, she was positively divine. She’s everything a great dancer should be: musical, physically strong, fearless, animated, and loaded with stage presence. Her remaining performances are in “Ballet Imperial” on the all-Tchaikovsky program (June 1), “Swan Lake” (July 5 and July 9 matinee), and “Giselle” (July 12).

Let me keep it simple: You’ve just got to see her dance. For tickets, call 212-362-6000.

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The sad event is upon us: New York City Ballet dancer Peter Boal will give his farewell performance this Sunday, June 5.

If you can’t make that performance, there are a few last-minute ways to catch his dancing. On June 1, he will dance “Agon.” (And the rest of that program – an all-Stravinsky lineup – happens to be quite good: Divertimento from “Le Baiser de la Fee,” “The Cage,” and “Concertino”). On June 3, he will dance “Opus 19/ The Dreamer.” And on June 4 (matinee) he will dance “The Goldberg Variations.”

Artists like Mr. Boal – a thorough master of his craft – do not come around often. He will be sorely missed. For tickets, call 212-307-4100.