On a Saturday evening in early October, there was a current in the lobby of 220 South Michigan Avenue that hummed and snapped like a tesla coil. Refractive gowns and flapping coattails boosted the signal of the hushed word bouncing off everyone’s lips: “Muti.” It was the grand gala celebration of Riccardo Muti’s inaugural season as music director of the Chicago Symphony Orchestra, and it marked the return of the virtuosic violinist Anne-Sophie Mutter after a 20-year absence from Orchestra Hall. Two supernovas of the classical universe were together for one night only.

But, according to a few musicians who had gathered to play, something was amiss backstage. Muti, a robust and youthful 69-year-old, did not look himself.

Earlier that day at rehearsal—the symphony’s first and last with Mutter—the maestro modestly confessed he wasn’t feeling well, gestured toward his midsection, and brushed it aside. At 6:30 p.m., half an hour before showtime, a select group of CSO officials privately discussed Muti’s condition. If he couldn’t conduct, who could take his place on the podium?

One hour later, the CSO Association president Deborah Rutter walked onstage and confirmed the crowd’s worst fears. Muti was out. The show would go on, conductorless. Two champions stepped forward: The concertmaster, Robert Chen, would lead from his seat, and Mutter would cue the orchestra while she performed Beethoven’s Violin Concerto.

The stern-browed Mutter wasn’t interested in coddling the orchestra with a mild performance. Her instrument burned fiercely through passages, but she tripped in the third movement—a brief, barely detectable moment when she lost her place in the music. But she did not fall. With Chen’s guidance, this sage orchestra recalibrated instantly and followed Mutter to a vigorous finale. The electricity traveled to the members of the audience, zapping them out of their seats with frantic applause.

We wish the maestro a speedy recovery, but we thank him for this night. His illness reminded us that the symphony has more than one star—it has 100.

Photograph: Jeff Schear