Two sisters share the surprising highs and cringe-worthy lows of social media fame, when their most private thoughts become incredibly public in this fresh and funny debut novel.

Sisters Cassie and Sid Sunday have not done a bang-up job of keeping in touch. In their defense, it hasn’t been easy: life veered in sharply different directions for the once-close sisters. Today, beautiful and big-hearted Sid lives an expat’s life of leisure in far-off Singapore, while harried, iPhone-clutching Cassie can’t seem to make it work as a wife and mom to twin toddlers in Manhattan.

It doesn’t help that Sid spurns all social media while Cassie is addicted to Facebook. So when Sid issues a challenge to reconnect the old-fashioned way—through real, handwritten letters—Cassie figures, why not?

The experiment exceeds both of their expectations, and the letters become a kind of mutual confessional that have real and soul-satisfying effects. And they just might have the power to help Cassie save her marriage, and give Sid the strength to get her life back on track.

But first, one of Cassie’s infamous lapses in judgment comes back to bite her, and all of the letters wind up in the one place you’d never, ever want to see them: the Internet.