Isabella Caravella is dreading summer. She doesn't want to spend a month at a lakeside resort with her parents and the families of her dad's coworkers, especially when she discovers that two of the kids go to her school. She thinks Bailey and Ava are beyond weird--and they're not exactly thrilled to see Izzy, either. Izzy has been their tormentor, the leader of the pack of girls who made their first year of middle school so unpleasant.

Once Izzy discovers that the other kids have been spending their summers together for years and she's the outsider, she realizes she's going to have to change her bossy, stubborn ways if she wants to fit in. Bailey and Ava turn out to be kind and welcoming, and Izzy actually wishes she were more like them.

Back home, Izzy knows that things are probably going to be different. Ava and Bailey were great summer friends--but are they really forever friends? Can Izzy prove that she really does have the potential to be a true friend? Or is she stuck playing the mean girl forever?