Clarissa Darling is a teen girl dealing with typical pre-adolescent concerns such as school, boys, pimples, wearing her first training bra and an annoying little brother Ferguson.
When Olvia's brother wants to sell his motorcycle, Clarissa stores it in the garage and plans to later buy it. Her parents have always told her she couldn't get a car but they never mentioned a motorcycle...
Clarissa has a history assignment: take something old, tired, and worn out, and reinvent it. So Clarissa tries to reinvent her mom.
Clarissa learns a few lessons about responsibility when she becomes the editor in chief for her school newspaper.
Clarissa has her work cut out for her, when Piper, the daughter of one of her mom's old school friends comes to stay and is far from friendly.
Clarissa and Sam go to a party dressed as cool, hip, outrageous characters. Clarissa dons a wig, a tatoo, and a nose ring and decides to call herself Jade. At the party, she falls for a cute guy named Paulie. But Clarissa isn't sure if he's interested in her or the ficticious Jade. Meanwhile, Ferguson finds a stray cat who he names William F. Buckley and tries to hinder his parents from looking for the real owner.
Clarissa and Sam sign up for the school intern program to help them get aquainted with the real world. Clarissa ends up as Mr. Ander's intern and Sam is Mr. Darling's intern. However, trouble ensues when they both get annoyed with each other's fathers.
Marshall joins an architectual firm after receiving some very generous offers from the corporation. But the money doesn't seem to make up for how the entire family feels about the firm. Meanwhile, Clarissa tries to write an essay to win a scholarship for college.
After Clarissa is given a class assignment to invent and market an environmentally safe product, she teams up with her mom to market Bouncy Balls- yummy health treats that bounce when they're dropped on the floor. The business doesn't work out so well when Clarissa feels left out of marketing process. Meanwhile, both Ferguson and Marshall have their tonsils removed.
Clarissa is given her own advice column in the school paper. She soon finds out that giving people good advice isn't as easy as she thought.
Ferguson orders a pair of new mind control glasses and decides to try them out on the family. However, Clarissa decides to fight back too as she has the same mind control glasses.
Clarissa discovers that real science can be really weird. After interviewing a woman who supposedly spotted a UFO, Clarissa decides to get to the bottom of the UFO phenomena herself.
When Clarissa decides to protest against animal testing at Woolcott Industries, she and Sam end up getting arrested! But afterward they can't decide whose parents they should call from the police station.
It's a sad day as Clarissa complete her last assignment for the Dispatch - an article dedicated to the future.. where will everyone be in 20 years?