Susan Berman (IMDB indicates she has just seven acting credits in her career, stretched across 25 years) plays Wren, a feisty, curly-haired scenester. She seems somewhat tied to New York club culture (the Peppermint Lounge is prominently used as a location), but has no real commitment to the music and people beyond how much she can exploit them for financial support.
She has no income, drifts from friend to friend (whoever will take her) and unconvincingly lies about her homeless poverty. The heart of the plot is her pursuit of two men: a sweet newcomer from Montana who's living in his decrepit van (Brad Rinn) and a struggling rocker (real-life musician Richard Hell, who's quite solid as an actor).
It's interesting to view "Smithereens" in the context of other early-'80s films about young, trendy women (including Seidelman's big-budget follow-up, "Desperately Seeking Susan"). Wren's initial entrance (confidently plastering flyers with her face around the subway) suggests a spunky, independent, charismatic John Hughes heroine. Someone we'll fall in love with. So, it's a disturbing twist to discover that she's basically, well, a jerk. The girl is going nowhere fast, and there's no reason for anyone to care.
Underground legends the Feelies dominate the score, though two Hell songs appear too. A forgotten group called the Nitecaps also performs on camera. In the closing minutes, a young, skinny Chris Noth appears for a split-second as a transvestite hooker.