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.J. and his friends think that Ms. Todd is the strangest substitute teacher in the world, and they decide to investigate her.

When her substitute teacher realizes she is struggling in math, Judy is sent to a math tutor at the local college and soon is completely into the spirit of college life.

"When Milton Worthy learns his classroom's pet ferret is the evil mastermind behind a dastardly plot for world domination, it's more than just about any kid could handle. But then not every kid is the son of a member of the super-secret, super-awesome Society of Substitutes! Now it's up to Milton and his substitute teacher mom to save Beacher Elementary School before time runs out." -- Page [4] of cover.

When Mrs. Green is out sick, her students worry that their substitute teacher might be a giant monster who will hurl them into outer space.

Grown-up, former child detective Lottie Illes is back at her old middle school as a substitute teacher where she is asked to solve a mystery.

Sam, Lucy, and Antonio have a new substitute teacher, who happens to be the great-great-grandson of Orson Eerie, the evil scientist whose spirit possesses and infects their elementary school--and the friends are afraid he may be trying to bring Orson back to life.

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

While stuck in the school during a blizzard, Robert Arthur and his companions face off against an evil substitute teacher and an army of beasts.

When the origami pig that Song Lee made for her grandmother is seized by a substitute teacher, the usually well-behaved third-grader breaks a classroom rule to rescue it from the "June box."