Lara Ardeche, a glamorous sixteen-year-old, is elected homecoming queen at her Nashville high school, as her mother was years before. She works out daily on gym equipment supplied by her wealthy grandfather. She thinks her family is perfect: her mother and father are youthful and attractive, her younger brother is cute and smart, and she is popular, beautiful, and her father's "princess." Her best friend, Molly, is one of the few offbeat characters in her life; other friends call Molly "the Mouth." Molly is frank, funny, a little fat, and indifferent to the unsubtle slurs of the in-crowd.

Weeks after homecoming, Lara, who has never had a weight problem, begins to gain weight rapidly and inexplicably. Within months her weight soars to 200+ pounds. She is diagnosed with a rare "Axell-Crowne" syndrome, a severe metabolic disorder with no sure cure. Most of her friends abandon her, though Molly stays faithful and Jett, Lara's boyfriend, tries to maintain a relationship.

The family begins to fall apart. The father, it turns out, has been having an affair. They move to Michigan to get a "new start." But the affair continues, kids at the new high school are cruel, and Lara is miserable until she is introduced to a new, motley group of people through her piano teacher who shares her love of music and is about her size.

In a cross-generational, racially mixed jazz club she begins to think differently about who she is and on what basis real relationships survive. By the time her weight begins slowly to fall, she has come to terms with herself and the dysfunctions in her family in a whole new way, and at great cost. She still hopes to be thin again, but not because she any longer kids herself that a fashionably thin body is a key to happiness.