When first-grader Roscoe discovers that his stuffed pig is missing from his backpack, he accuses the class bully of "pig-napping" and gets even by taking the bully's teddy bear.
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.
Determined to win a trophy of some kind, first-grader Roscoe swaps a hand-knitted sweater from his grandmother for the chance to enter his new neighbor's very clever dog in a trick contest.
Mr. Docker, a new science teacher, is a crazy inventor who blows things up, uses potatoes for power, and has A.J. and his friends wondering whether science is for nerds or is the coolest subject ever.
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.
Timmy Failure is banished from practicing his detective skills in the wake of a missing tooth, a teachers' strike, and his mother's romance with a doorman, situations further complicated by the disappearance of his private notebook.
While his mother and doorman Dave celebrate their wedding, Timmy visits Florida where he forges a new partnership with Dave's nephew, Emilio, when a surprise newcomer shows up and he encounters a thieving six-toed cat.
A.J. and his classmates are convinced that new school librarian, Mrs. Roopy, has multiple personality disorder because she keeps pretending to be famous people.
Even though people say Mrs. Patty, the school secretary, is a witch and her husband is a ghost, A.J. decides to take the risk and trick or treat at their house because they are known to give out the best Halloween candy in town.