This novel debut feature by writer-director Damien Chazelle combines the low-key naturalism of early John Cassavetes with the heightened artificiality of an MGM musical, and the latter prevails. Shot with a handheld camera on black-and-white 16-millimeter film, the movie chronicles the circuitous romance between a shy waitress (Desiree Garcia) and a jazz trumpeter (Jason Palmer), with a few narrative detours involving the musician's other lover (Sandha Khin). The song-and-dance numbers are magical, especially an early jam session at a jazzbo party and a synchronized tap routine that interrupts the waitress's dull shift at a diner. But they have the unfortunate side effect of making the nebulous plot and vague characters even harder to tolerate. Integrating the tunes with the story has always been the primary challenge of the musical, exacerbated here by there barely being a story in the first place.