BallouHigh Schoolis located in the southeast part of Washington, DC, an impoverished urban area just a few miles from the Capitol Building. Only 5 percent of Ballou's graduates go on to finish college, thanks to the drug-and-crime problems sustained by the neighborhood's low economic stature. But under the tutelage of a tireless individual named Darrell Watson, a gaggle of Ballou's students have found a sort of raison d'etre in marching band. Yup, weird helmets, whirling flags, and instruments large enough to topple a kid; not the first things that spring to mind when thinking of inner-city youth, but the dedicated young people of Ballou High seem to live for it.

In the rousing documentary "Ballou," director Michael Patrei trains his lens on Watson and his generous volunteers, many of them former Ballou students. "I was determined to come back to Ballou to be a teacher and to do what I'm doing," Watson says, while another unpaid staff member puts it more succinctly: "Band is my life." She's not kidding either; the marching band practices every day after school and on Saturdays, and some of Patrei's most affecting shots find the seemingly inexhaustible kids honing their music and choreography on nearby streets, the boarded-up buildings in stark contrast to the open, unbridled enthusiasm of the band members.

We get to know some of the marching band's more prominent participants, like sousaphonist Lewis, a young man of great faith who runs for band president; as well as the magnetic Kenney, a percussion-playing jokester who nonetheless takes his role in the band very seriously. "Ballou" builds final-reel suspense via the school's participation in the High-Stepping Marching Band Competition, but it's really all about the unifying power of music as well as the difference a few impassioned people can make when they take it upon themselves to give back.