Well before Kathryn Stockett’s novel The Help (or the subsequent movie version) ever became popular, the much-admired playwright Tony Kushner (Angels in America) collaborated with composer Jeanine Tesori on this musical that traverses similar thematic and geographic territory. Based in part on Kushner’s experience growing up in Louisiana, the story is set in 1963 and deals with race relations. Its central character is a divorced African-American domestic who works for a Southern Jewish family. As ambitious as any theatrical opus of the new millennium (including Next to Normal), Caroline, or Change is what is called a through-composed — or “sung-through” musical, whereby conventional dialogue is all but dispensed with, leaving its actor-singers to emote it all through a score that here merges spirituals, blues, Motown and classical styles with klezmer and folk music. The critical reaction to this piece — after its 2003 Off-Broadway debut and its later, disappointingly brief 2004 Broadway run — was uniformly enthusiastic and admiring, but some of the well-thought-out responses to its structural difficulties also help explain the show’s somewhat lukewarm popular reception. Unlike Hairspray — another musical that explores race issues in the ’60s — COC resists easy pop tunesmithing or hopeful solutions via upbeat ensemble numbers. Street Theatre Company’s production of the Nashville premiere is under the direction of versatile actor Peter Vann and features some performers who may not be readily known to Music City theatergoers, including DaJuana Hammonds, Benee Wisdom, Shawn Lewis, Dalton Tilghman, and Brooke Davis in the title role. The talented Janette Bruce, a standout in Keeton Theatre’s recent Into the Woods, is also in the cast. Expect to be challenged — and more than likely rewarded.