There is never a shortage of backstage drama at the Metropolitan Opera. But in the company’s 137-year history, there has likely never been a production with a birth as tumultuous as that of the high-stakes new staging of Puccini’s “Tosca,” opening on New Year’s Eve.

With opulent sets evoking 19th-century Rome and a starry cast, the new “Tosca” was meant to appeal to operagoers still lamenting the loss, nine years ago, of a beloved Franco Zeffirelli extravaganza that had been playing since the 1980s. But the company watched in horror as a series of unfortunate events cost the staging its original heroine, hero, villain and maestro. In a field in which singers are typically hired up to five years in advance, the Met had to quickly draft a pair of fast-rising stars, the soprano Sonya Yoncheva and the tenor Vittorio Grigolo, who have never before sung the roles.

But the most severe blow landed this month, when James Levine, who in July had stepped in as a high-end replacement conductor, was suspended amid accusations of sexual misconduct that rocked the classical music world.

“I’ve never been in a situation like this in my entire career,” David McVicar, the production’s director, said during a recent rehearsal break, tilting his head back and slowly sliding off a couch for dramatic effect. “It’s been like ‘Groundhog Day’ sometimes. Just when you think you’ve made progress, someone else is gone, and someone else is coming in. The sheer stress of it is something I’ve never been through.”