Allie Finkle is excited when a new girl, who comes all the way from Canada, joins her class at Pine Heights Elementary. Now Allie wont be the new girl anymore! But her excitement turns to dismay when the new girl, Cheyenne, starts telling everyone in the fourth grade what to do! Soon Cheyenne has everyone, including Allies best friends, Caroline, Sophie, and Erica, believing that if they dont do what she says, theyll be what Cheyenne accuses them of being - babies! But Allie isnt sure shes ready to be all grown-up yet. Not if it means chasing boys at recess, not playing her favorite games anymore, and especially...not being herself!