A.J. and his classmates are convinced that the new school librarian, Mrs. Roopy, has multiple personality disorder because she keeps pretending to be famous people.
Four fifth-grade students--a geek, a class clown, a teacher's pet, and a slacker--as well as their teacher and mothers, each relate events surrounding a computer programmed to complete homework assignments.
A.J. and his friends get a Personal Digital Assistant named Miss Porter as a substitute teacher, who can order pizza and tell endless jokes, but grows power-hungry when her system is changed and tries to take over Ella Mentary School.
A school trip to the natural history museum goes awry when the curator, Ms. Krup, loses her giant cockroach and A.J. and his friends decide to explore the museum in the middle of the night.
When boring Mr. Loring retires, A.J.'s class gets a new music teacher who raps, break-dances, and thinks he has what it takes to become a famous musician.
Tired of following the strict rules of their grumpy replacement principal, second-grader A.J. and his classmates try to find a way to bring back eccentric but lovable Principal Klutz, who was fired for bringing a wild turkey to the school's Thanksgiving Day assembly.
