It's Riley Ricci-Chase's first wedding anniversary, and she's living a perfect life in London with her utterly devoted husband, Tristan. So what if his parents and insufferable cousin Milo work Riley's last nerve? She has Tristan.

The next morning Riley wakes up exactly one year later. No wedding ring. It's Milo by her side. And Tristan is a happy new father--with another woman. None of this is surprising to anyone. Except Riley. Where does she go from here? With every new tomorrow, she's moving backward through time to face a year she's already lived, one she's completely unprepared for.

Unless this is some cosmic prank, Riley is on a journey with a lot of questions. What went wrong with Tristan? How in this mind-blowing flip side could it have gone right with Milo? And where do her future and true love lie? To find out, Riley will have to wait and see what yesterday brings.