Trombones and sousaphones bellowed hysterically. Saxophones brayed, badly out of tune. Drums rumbled behind or ahead of the beat.

Considering that the biggest game of their football season was five days away, prospects did not look good for the most revered marching band in New Orleans, the Purple Knights of St. Augustine High School.

And a great deal was at stake. For St. Augustine and for this shattered city, the band's halftime show would represent a small but symbolic resurgence of indigenous music in a city that has lost most of it. So in a blue-collar neighborhood where boarded-up houses still bore spray paint indicating how many corpses had been found inside, an inspired bandmaster and a group of high schoolers struggled to keep alive a New Orleans rite.