Fiona and Cassie are best friends for life. No one else can make Fiona laugh like Cassie can, and that meant everything when Fiona’s parents were divorcing. They love each other in spite of their (many) differences, and even though Cassie cares a little too much about being popular, Fiona can’t imagine life without her.

Until Fiona’s diary is stolen at school, and everything changes.

It’s a middle schooler’s worst nightmare come true: not only is Fiona’s diary taken, but it’s read out loud on the bus by the popular kids that day. Even worse: Cassie was there, and she didn’t do anything to stop them. And for some reason, now she’s ignoring Fiona. Suddenly the whole world has shifted.

Life without a best friend is confusing, scary, and maybe impossible. But as Fiona navigates a summer of big changes, she learns more about herself-and friendship-than she ever thought possible.