George and Harold, and their doubles, Yesterday George and Yesterday Harold, have a good thing going. Two of them go to school, while the other two hide in the tree house and play video games all day-then they switch! But when their malicious gym teacher, Mr Meaner, creates a method of mind control that turns their fellow students into attentive, obedient, perfect children, the future of all humanity will be in their hands!

Alexander has just moved into Stermont, but the elementary school is being torn down, his new classroom is located in the hospital morgue, a notebook he finds is full of information about monsters--and everywhere he turns there are spooky balloon men determined to attack him.

Alexander is used to finding monsters everywhere in Stermont, but now the school is being turned into an icebox by giant meat-eating vegetables--and his friend Rip has gone missing.

Alexander and his new friend, Rip, are worried that the worms the rain has brought out are really the megaworms that Notebook of Doom describes but they soon discover that the night crawlers are trying to warn them about the monster tunnel fish that are threatening Stermont Elementary.

Kiki and her best friends, Coco and Lulu, all live on Lotus Lane, attend Amber Acres Elementary School, and have their own club, so when a when a Japanese girl named Mika moves in next door and also chooses fashion design for her art project, Kiki is seriously annoyed.

Sam Graves discovers that his elementary school is alive and plotting against the students, and,as hall monitor, it is his job to protect them--but he will need some help from his friends.

Clyde is a hyperactive kid, and his twin sister, Claudia, does her best to keep him out of trouble--but after a class field trip to the science museum, and a zapped banana, he suddenly finds that excitement transforms him into a real monkey, which may help him catch the thief who took the golden monkey.

There is an elegant substitute teacher in class today, but Katie's attempts to impress her keep going wrong.

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.