For two years Amira had been the second trumpet in the Lincoln Middle School jazz band, which meant she learned every solo and played none of them. She practiced them anyway, in the garage, with the door pulled halfway down so the neighbors would only get half the noise.

On the Thursday before the spring concert, Ronnie Vasquez broke his wrist skateboarding, and Mr. Ferreira handed Amira the solo folder without any ceremony at all. “Bar forty-one,” he said. “It's yours.”

She had imagined the moment so often that the real thing arrived secondhand, like a jacket someone else had already worn in. At the first rehearsal her hands shook so badly that the opening four bars came out thin and apologetic. The band played on. Mr. Ferreira did not stop them, and somehow that was worse than being stopped.

That night she did not practice the solo at all. She practiced the two bars before it, the ordinary measures where the trumpet only holds a single note under the saxophones, until she could play them without thinking about what came next.

On Saturday the stage lights turned the auditorium into a warm wall of dark. Amira found the single note under the saxophones and held it. When bar forty-one arrived she was already inside the music, and she walked through the door without noticing she had opened it.