Ethan Brand (Alessandro Nivola), frontman for a small-venue alt-rock band about to splinter thanks to his drunken tantrums, is met backstage in Little Rock by a twitchy woman (Elisabeth Shue) who claims he’s the father of her 13-year-old girl. Mom’s about to check into rehab, so Ethan begrudgingly agrees to bring young Janie (Abigail Breslin) on the tour bus; he soon discovers that the lass is a talented singer-strummer. There are no surprises in David M. Rosenthal’s film, which tries to toughen up the standard, soggy damaged-parent-child healing arc with rawk signifiers: anxiously appropriating a Clash song for its title and having its characters say “South by Southwest” three times too many. Nivola and Breslin sing and perform the original numbers (written for their characters by Eef Barzelay and Gemma Hayes), welcome interludes that provide respite from Rosenthal’s lousy script. Although Nivola, sporting a variety of skinny ties and a neck tattoo, is additionally saddled with a disgraced-son-of-fortune backstory (Ethan’s late-act scene with his mother, played by Frances Fisher, is the movie’s worst), he establishes a nice rapport with Breslin, transitioning well from her cute-dumpling roles and proving to be an excellent onscreen crier.