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.

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.