Twins Andie and Caitlin are best friends but they couldn't be more different. Andie loves sports and hanging out with her friends — Caitlin is passionate about music and loves learning at school. Now that junior high is starting, the girls will finally get a chance to pave their own way. They can't wait! But when Caitlin discovers she'll have to pass a fitness test or spend every day after school doing gym, she fears her year is ruined before it even begins. The girls make the switch. While Andie passes the fitness assessment for Caitlin, Caitlin goes to class for Andie. Everything goes great — maybe TOO great. Now it seems like the girls keep wanting to change places "just one more time." With each switch the girls get in deeper. Will they be able to straighten things out before they're in over their heads?