Riley Wynn went from a promising singer-songwriter to a superstar overnight. When Riley's ex-husband claims her hit song is about him, she does something she hasn't in ten years and calls Max Harcourt, her college boyfriend and the real inspiration for the song of the summer. When Riley asks him to go public as her songwriting muse, he agrees on one condition: he'll join her band on tour. As they perform across the country, Max and Riley start to realize that while they hit some wrong notes in the past, their future could hold incredible things. And their rekindled relationship will either last forever or go down in flames.