A group of three children discover that their teacher is actually an alien from another planet and may be plotting an invasion of the Earth.  Peter is kind of a class nerd, and Duncan is a class bully.  Susan is the first to realize that their teacher, Mr. Smith is actually an alien, and she gets the boys to help her investigate the teacher and uncover his fiendish plot and expose his true identity.

For a time, the alien, whose real name is Broxholm, kidnaps Peter and takes him to outer space.  It turns out that aliens have been studying humans on Earth to try to decide what to do with them.  Many aliens think humans are bizarre and dangerous, and they are trying to decide whether the human race should be left alone, carefully controlled, or destroyed altogether.  The kids eventually team up with Broxholm to convince the Interplanetary Council not to destroy or invade Earth.

Over the course of the series, Duncan becomes less of a bully.  Peter discovers that he has telepathic abilities.

Books in the Series:

My Teacher is an Alien

Everyone thinks that their teacher is a little weird.  Nobody in Mr. Smith’s class really likes him, but Peter, Susan, and Duncan discover that he is actually an alien from outer space.

My Teacher Fried My Brains

Duncan discovers that there is another alien posing as a human at their school.  At first, Duncan thinks he knows who the other alien is, but he may be wrong.

My Teacher Glows in the Dark

Peter, who has returned to Earth with Broxholm, explains to the others where they’ve been in the last few months that he was missing.  He explains to the others that aliens are trying to decide if humans are worth preserving or if it is too dangerous and should be destroyed before they achieve interplanetary travel and become more powerful.  Together they try to prove to the aliens that humans have redeeming qualities.

My Teacher Flunked the Planet

The kids and their alien teachers go to the Interplanetary Council to convince them to leave Earth alone and let humanity continue to develop.