The first alien child on Earth, Pleskit, makes his way to Colville Middle School. Fellow student Tim Tomkins tries to befriend the alien in order to learn more about him. Trouble ensues when Pleskit's bodyguard loses track of him.
When Pleskit gets nervous, his antenna gives off electric sparks, causing the students believing that aliens have the ability to blow up Earth. This causes the students' parents to panic and try to get Pleskit out of Coville Middle School.
In order to help Tim win a science contest, Pleskit bends the rules by using his superior knowledge. The boys create a way for cow manure to fuel cars. Unfortunately, the fuel turns explosive, and someone has stolen the remainder of it.
Pleskit brings a strange plant to the Woodlander Jamboree. Trouble ensues when the plant starts to turn all of the Woodlanders into zombies, including Pleskit.
It's Valentine's Day and Pleskit creates a magic powder to make people fall in love with each other. The plan goes awry when Mrs. Weintraub falls in love with Principal Grand, and Lindy falls in love with Pleskit instead of Tim.
Tim brings his hero Captain Driscoll from the Tarbox Moon Warriors to life and takes him to school. However, when Jordan steals the solution that was used to bring Driscoll to life, it gets spilled, and a spider becomes a giant.
Pleskit brings a Veeblax (a small, strange animal) to school. After it eats all of Tim's lunch, Tim and Pleskit deduce the Veeblax is feeling ill due to gas. They're wrong when the Veeblax starts to grow larger than the entire school.