Could it be that the MBC will be eliminated? After a virus breaks out in the club, the MBC is put on quarantine and sent up in space. They only have a few minutes left before the clubhouse implodes!
Doodoo comes back to earth asking for the MBC's help again. After thinking that Chris is an emperor, he's now asking Sam to pretend she's a princess to help him solve a crisis with the Dundethunkers that threaten to eat the planet! Yet another mission for the MBC!
Students in Singletown Middle School are thrilled to participate in the pet show that the school has organized. This year's jury is the famous Morag...but is she really famous? Why is it that no one has heard of her before? And what is the secret plan she's trying to pull up?
The MBC is shocked when Mr Smith's sister, Aunt Frida, comes back to visit them, except this time she informs them that...she's married! And her husband is a famous opera singer! But things are not what they seem, and Moochie is certainly full of surprises! In the meantime, Sam gets stuck with Aunt Frida who is working on a secret recipe.
The MBC encounters a weird-looking alien, Mimi, who seems to get everything ready for a wedding in Singletown.
While Cathy and Chris battle the ever-increasing Annihilator forces in the present, Danny and Sam are in the past trying to alter the course of the future and prevent Mark from ever getting his hands on the tape. However, their efforts keep failing and, back in the present, the Annihilator mother ship has arrived with its Death-Star-style beam to flatten the town.
Mark finds a "training tape" of the MBC kids and tells everyone in school about the alien-fighting club. With their secret discovered, the MBC kids are idolized by some classmates and jealously mocked by others. Several vengeful aliens also learn the kids' identities and set out to destroy them.
Mr. Smith puts the MBC in charge of protecting a small black orb. What they don't know is that the orb actually contains an entire galaxy! And things get really tricky when a vicious spider alien confuses the orb with her missing egg! Meanwhile, Mark challenges Danny to a bowling competition on his own private bowling lane.
The MBC investigates when people start mysteriously disappearing all over town. It turns out to be the work of "Beady" - the evil twin brother of the speed morpher, Speedy. He's determined to set up a museum-like exhibit of "The Galaxy's Strangest Creatures" and tour around the universe.
When Singletown experiences some strange weather patterns, the MBC discovers that the entire town is covered with an alien Jellynerp. The creature was placed there by the local weatherman - actually an alien - who is tired of reporting the weather and wants it to be the same every day. A sound plan, except for one minor detail: now the Jellynerp is hungry and it's starting to eat the town!
When Danny and Sam mess up a few assignments, the IGA commander sends down two droids to assist the MBC. But, while Chris and Cathy get along with the new recruits, Danny and Sam suspect that they're up to no good. Meanwhile, Mr. Smith recruits the MBC to help him plan Cathy's "Sweet 250" birthday party.
When an alien named Doodo mistakes Chris for an intergalactic Emperor, Chris goes along with it, thinking it will be fun. But things quickly get out of hand when the MBC discovers that there is an evil alien named Krungnar who is out to mandelbark the emperor's flaggins.
This action-comedy follows the adventures of four 10 year-olds protecting their town against alien invasion. Juggling school and top-secret monster busting can be tough, especially when your science teacher turns out to be an alien! Monster Buster Club, or 'MBC' as it is known, follows the exploits of Cathy and her friends on their mission to protect Singletown from troublesome aliens.