Overweight Wrenn Scott desperately wants to be popular and snag a hot boyfriend. Living with her single mom and younger sister, Karly, she lands a lead role in the high school musical, her voice for once overshadowing her weight. Pushing to get thinner by opening night, Wrenn's waistline shrinks as she learns all the wrong ways to lose weight from a new "it-girl" friend in the show. Meanwhile, her mom is falling for Phil, "a balding Channel 8 News-nerd"; her sister is wrapped up in her own share of middle school drama, and Wrenn's best friend has fallen for a guy she met online-but hasn't even seen yet! Topping it off, geeky stage manager Steven has a crush on her. But Wrenn doesn't want to be seen with him- she's holding out for a trophy boyfriend whom everyone will envy. By opening night, the old Wrenn has almost disappeared. After a crisis reveals her weight-loss tricks, Wrenn realizes there are much more important things than being thin, popular, or even dating a hunk.