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.

"Summer of 1999: Twenty-something Sawyer is balancing a new city, her suddenly-distant fiancée, her assistant job in publishing, and making a mark with her own writing. When she meets Nick, boyfriend to her fiancee's all-too-close female colleague -- seriously, since when is karaoke part of staying late to work on a case? -- Sawyer's lonely summer in New York takes an unexpected turn. At first she finds Nick salty and smug, and he finds Sawyer stuck...

Now high school juniors, Zoe, Maddie, and Angela continue to share "instant messages" with one another as one of them experiments with marijuana, another gets her first boyfriend, and the third moves three thousand miles away.