Pen, Will, and Cat met during the first week of their first year of college and struck up a remarkable friendship, one that sustained them and shaped them for years - until it ended abruptly, and they went their separate ways. Now, six years later, Pen is a single mother of a five-year-old girl, living with her older brother in Philadelphia and trying to make peace with the sudden death of her father. Despite feeling deserted by Will and Cat, she has always wanted them back in her life, so when Cat emails, asking her to go to their college reunion, Pen goes. What happens there sends past and present colliding and puts all of them on a journey that will change everything.