After learning about Sherlock Holmes, Humphrey the classroom hamster follows clues to try and discover why Mrs. Brisbane is gone and Mr. E, a fun but not very educational substitute, is taking her place in Room 26 at Longfellow School.
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.
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.
Atticus Hobart couldn't feel lower. He's in love with a girl who doesn't know he exists, he is the class bully's personal punching bag, and to top it all off, his dad has just left the family. Into this drama steps Mr. Looney, a 77-year-old substitute English teacher with uncanny insight and a most unconventional approach to teaching. But Atticus soon discovers there's more to Mr. Looney's methods than he'd first thought. And as Atticus begins to...
Seventh-grader Dave Sanchez and his talking gecko sidekick Sticky decide they must rescue an odious science teacher who has been kidnapped by the even more villanous Damien Black, who is masquerading as a substitute teacher in order to steal Dave's magic Aztec armband.