"Stephanie Perkins is the reason we write romance. Overdue is the book her readers have been waiting for." -Christina Lauren, New York Times bestselling author of The Paradise Problem

Ingrid Dahl is a cheerful, twenty-nine-year-old librarian living in the cosy mountain town of Ridgetop. She and her boyfriend since college, Cory, have never discussed marriage; they're perfectly happy with the way things are. But when Ingrid's sister announces her engagement to a woman she's only been dating for two years, Ingrid and Cory suddenly feel pressured to start thinking about the inevitable: marriage and kids.

The thing is, neither of them has ever been with anyone else. Shouldn't they sow their oats before settling down?

They make the unorthodox decision to separate for a month to date other people, assuming that at the end of it, they'll reunite and start planning their nuptials. And Ingrid has the perfect man in mind for this relationship sabbatical--Macon Nowakowski, her cantankerous and completely adorable coworker for whom she's had a crush for years.

But of course the best laid plans often go awry, and when Ingrid and Cory meet at the end of the month to resume next steps in their relationship, it's clear neither of them is ready to get back together...