A fun new boy has just moved in next door to Grace's best friend, Mimi. When Grace has to go away on a family trip during school, she is terrified that when she comes back Mimi will be best friends with Max instead! After her trip, not only does it seem her fear has come true, but Mimi is even friends with the disgusting Sammy. Now Just Grace has to team up with two other Graces in her third-grade class for a school project, including the Big Meanie.