Los Angeles public schools lend musical instruments to over a thousand students a year, and one workshop keeps them playable: a small crew of piano, string, brass, and woodwind repair technicians working out of a converted warehouse. The film follows four of them, including a piano technician who fled genocide in Cambodia and a brass repairman who rebuilds trumpets and trombones dented by years of school bus rides and gym lockers, as they explain how they learned their trade and why they stayed in it for decades. Interviews are intercut with footage of the students who receive the repaired instruments, several of whom describe what playing an instrument means to them when little else at home is stable. The camera stays close on hands working solder, felt, and brass, showing the specific, unglamorous skill involved in reviving a battered tuba or a cracked violin. It is a small, plainly told story about the last people in a shrinking trade and the free program that depends entirely on them.