The now-famous first alien child on Earth, Pleskit, makes his way to Colville Middle School for the first time. Fellow student Tim Tomkins tries to befriend the alien in order to learn more about him. Trouble ensues when Pleskit's bodyguard, Robert McNally, loses tradck of him.
When Pleskit gets nervous in front of the class, his antenna gives off electric sparks, causing the students to believe 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.
Trouble ensues between Pleskit's parent mentor Meenom and Ms. Thomkins when Ms. Thomkins nearly kills Pleskit by giving him a glass of soda.
Pleskit takes his Grandpa's brain in a jar with him to school, only to lose it in the process. It ends up in the wrong hands- Jordan's.
In order to help Tim win a science contest, Pleskit bends the rules by using his superior knowledge to help Tim. The boys create a way for cow manure to fuel cars. However, there's trouble when they find the fuel they've created turns explosive and someone has stolen the remainder of it.
Pleskit brings a Veeblax (a small, strange animal) to school. After it eats all of Tim's lunch, including bologna (no aliens eat meat), Tim and Pleskit deduce that the Veeblax just must be feeling ill due to gas. They figure out that they're wrong when the Veeblax starts to grow larger than the entire school.
There has been a lot of singing going on at Coville Middle School latley and no body knows why. What will happen if no body can stop singing!
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.
While Pleskit is at the Thomkins apartment with Ms. Thomkins, his electrical energy makes all of the appliances in the apartment go crazy.
Tim becomes trapped in the body of what he will look like when he becomes an adult.
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 giant.
It's Pleskit's first dance, but it doesn't turn out well when The Blur, Pleskit's fellow female alien nemesis, comes to the school.
When Pleskit has a bad day and realizes that he'll never be accepted, he decides to head back to his home planet.
Tim and Pleskit want to join the upcoming talent show going on at Coville Middle school. But unfortunately, neither of them play any instruments. As usual, Pleskit is there to save the day. He has an alien amp and when you plug in your instruments, you can play them. So they enter the talent show, but they soon use it too much it, causing it to explode and create a noise that will have ill effects on humans if heard. And it just so happens that someone has recorded it on a tape.
Tim is getting bored of his everyday routine. One day after math class, he goes bak to his locker and inside finds a letter saying for real excitment, he should press a particular silver button. He finds out that Blur wrote the letter, but decides to push the button anyway. He gets wisked into a Zartopian virtual reality game where he cannot return home until he wins. Zartopia however warps the memories of the player, so he goes through the levels playing with things he's familiar with, like algebra and Principal Grand. After 3 levels, he returns home safely with a better connection to a certain blue alien.
Ms.Buttsman is incharge at the embasie and she is planning on cancelling christmas! This upsets Pleskit and Tim very much, especially because it would be Pleskits first. As Ms.Buttsman drifts off into a deep sleep she is visted by 3 ghost's-the ghost of christmas present, past, and future. She is not impressed at what they show her and decides to give christmas back.
Pleskit has invented a machine much like a lie detector. Tim hooks Pleskit up to it to find that he does not lie at all. However, when Tim gets hooked up to it he lies so much the machine explodes causing him not to lie at all!
Tim is over at Pleskit's house and Tim finds out about the Invisiblunker. Pleskit brings it to school the next day, and Tim uses it to try and find out more about Lindy before she moves. He tries to impress her, but it all goes down the drain because Lindy thinks he's just plain weird! When Lindy and October are in the girls bathroom, Tim follows them, and overhears October ask Lindy what she really thinks of him. After Lindy states that she thinks Tim's a dork, he wants to stay invisible forever. And that could be possible if Pleskit, Mcnally, and Lindy aren't able to find him soon! In the end, it turns out Lindy really does like Tim, but unfortunately it's too late for him and Lindy to become anything.
Pleskit has invented a new invention called the Pooverizer 2000. It looks like an ordinary human pen, when really Pleskit uses it to zap his pet Veeblax's poop when he taking him for a walk so he doesn't have to clean it up. Pleskit asks Tim to walk his Veeblax one day after school, meaning he gets to use the Pooverizer 2000. As Tim is walking the Veeblax, he needs to stop and do his buisness right in front of the store Tim's mother is shopping in. When the Veeblax is done, he pulls Tim, causing the Pooverizer 2000's aim to go awry. It ends up pointing at the super market Tim's mom is shopping in causing her, and the store to be pooverized!