Winnie's thirteenth year brings many joys and challenges as she negotiates her relationship with her first boyfriend and realizes that change is inevitable in her friends, family, and even herself.

Winnie relates the events of her twelfth year and the many changes in her relationships and in her attitude toward growing up.

Through "instant messages," chronicles the struggles best friends Maddie, Angela, and Zoe face during their freshman year in college, each of them in a different state, two wondering if their romantic relationships will last, and one determining that roller derby is the key to keeping the trio close.

Throughout their senior year in high school, Zoe, Maddie, and Angela continue to share "instant messages" with one another about their day-to-day experiences as they consider college, sex, the importance of prom, and the inevitable end of their inseparable trio.

Winnie's celebrates her unique style through her first year with a double-digit age as she has many new experiences, from the high of spending time in New York City with her aunt and big sister, to the low of her two best friends suddenly becoming interested in boys. Includes bonus chapter from next in the series, Eleven.