- Directors: Bo Welch
- Producers: Brian Grazer
- Writers: Dr Seuss, Alec Berg, David Mandel, Jeff Schaffer
- Genres: Adventure, Comedy, Family
- Actors: Mike Myers, Alec Baldwin, Kelly Preston, Dakota Fanning, Spencer Breslin, Amy Hill, Sean Hayes
The movie starts with an inside look of Joan’s (played by Kelly Preston) job at Hank Humberfloob’s Real Estate agency, where the employees there are forced to clean their hands constantly either with a sink or a Hand Sanitizer. When Joan is called back to work, she gets a sleepy babysitter to babysit her kids, Conrad (played by Spencer Breslin) and Sally (played by Dakota Fanning). Conrad, a 8-year-old boy has 2 problems: He is constantly doing the exact opposite of what he’s supposed to do and causing trouble, and Sally, Conrad’s 7-year-old little sister who tries to stop Conrad’s trouble making. Their next door neighboor, Lawrence Quinn or Larry as Conrad always calls him (played by Alec Baldwin) threatens to marry Joan, and send Conrad away to a military school 8 hours away from home. When Joan leaves, their babysitter, Mrs. Kwan (played by Amy Hill), invites the children to sit with her in the living room and watch television, and then falls asleep. Not long after, it starts to rain and storm outside and the children get bored. But then there is a thud somewhere in the house, and as the children go investigate, the Cat in the Hat (played and voiced by Mike Myers) appears. After The Cat puts Mrs Quann in the closet, the Fish starts arguing about him being here. The Cat ignores the Fish (even insulting it, saying “Come on, kids, are you gonna listen to him!? He drinks where he pees!”) and then convinces Conrad and Sally to sign a contract which will allow them to have all the fun they want, and will stop anything bad happening.
They chase him towards a birthday party, and the Cat gets whacked by a strong kid, imagining himself swinging, and wearing a dress. Larry grabs Nevins, and heads for Joan’s office. Conrad, Sally, and the Cat manage to get Nevins back by catching up with a vehicle called SLOW and tricking Larry into handing over Nevins and the crab lock. They get away from him and into the dance party room where dance music is playing. While The Things distract Joan and Larry, the trio get back home, unaware that the babysitter has fallen off the crate to answer a phone call from Joan and that all terror is breaking loose as the crate erupts. When Conrad, Sally and Larry first enter, the house looks spotless. But when the cat reappears at the doorway, Larry starts sneezing and stumbles backwards, only to have the floor rip out from under him as if it were paper and send him falling from a massive high cliff into the Cat’s world. The children gasp at what has become of the house After a walk on the suspended in mid air front hall carpet and a thrilling ride on Ms Kwan down a large “water slide” ride flowing with pink stuff, they find the crate, now with a big tornado spinning on top of it that is sucking up everything nearby. Conrad eventually manages to put the lock back on the crate, causing the distorted house to straighten itself, but then it collapses, leaving wreckage everywhere. They send the Cat out, but he comes back with Thing 1 and Thing 2 and a cleaning machine called the Dynamic Industrial Renovating Tractormajigger (DIRT). They clean up the mess, and the house is clean and back together. The Cat leaves, just in time for Joan to come home. Ms Kwan wakes up and tells Joan that the children were “angels.” But then Larry Quinn barges in, covered from head to toe with purple slime and starts telling Joan about the mess and the Seussian world. She sends him away, and things go back to normal. The party goes as scheduled and the kids are told that there purple frosted cupcakes are a “huge hit.” The camera then zooms out to reveal that The Cat was telling the story, and during the credits it’s revealed that Annville is underneath the Universe.