Brady (Ross Lynch) and Mack (Maia Mitchell) have returned home from their adventure with the cast of the '60s movie Wet Side Story. Summer is over and it's time to head back to high school.
However, the two find themselves drifting apart when suddenly, Lela (Grace Phipps) and Tanner (Garrett Clayton) from Wet Side Story wash ashore and want to go to school with them.
Lela wants to stay and study with Mack, but her friends back home start disappearing from the movie. They all come to the "real" world to get their friends back before anyone else gets zapped out of the movie and the entire movie stops existing. Mack and Brady try to help them and along the way, discover that their differences aren't that big after all.