Roberta Guaspari's (MERYL STREEP) Navy husband has just run off with a friend of hers, leaving the stay at home mom to care for their young sons, Nick (MICHAEL ANGARANO) and Lexi (HENRY DINHOFFER) and forcing them to live with her mother, Assunta (CLORIS LEACHMAN).
A chance encounter with a former classmate and current writer, Brian Sinclair (AIDAN QUINN), however, changes her life forever. Knowing her love for music, Brian suggests that Roberta contact Janet Williams (ANGELA BASSETT), the principal of an East Harlem school, about staring a violin class there.
With few other options, Roberta packs up the kids, heads into a neighborhood completely foreign to her, and just manages to convince Janet to hire on her a temporary basis, much to the chagrin of Dennis Rausch (JOSH PAIS), the resident, but uninspired music instructor.
At first, things are rough. The students, including DeSean (JADE YORKER), a troublemaker, Lucy (VICTORIA GOMEZ), who has a penchant for snapping her fingers, and Guadalupe (ZOE STERNBACH-TAUBMAN), a young girl in leg braces, are either uninterested in learning the violin or simply no good at it. Another student, Naeem (JUSTIN SPAULDING) is pulled from the class by his bitter mother.
To make matters worse, Roberta's staying with Brian, the only person in town she knows. Despite a romance breaking out between them, however, he then leaves for a several month writing assignment. And except for second grade teacher Isabel Vasquez (GLORIA ESTEFAN), none of the other instructors like her.
Yet she perseveres and years later, despite a confrontational teaching manner, has become quite successful and admired. Her kids, Nick (CHARLIE HOFHEIMER) and Lexi (KIERAN CULKIN) are now teens and conspire to fix her up on blind dates, such as with Dan Paxton (JAY O. SANDERS). Even so, her attention remains on her course that, due to budget cutbacks, suddenly faces academic extinction.
Thus, with the aid of Janet, photographer Dorothea von Haeften (JANE LEEVES) and a host of acclaimed violinists, including Itzhak Perlman, Arnold Steinhardt and Isaac Stern, Roberta sets out to save her beloved violin class.