The Cat in the Hat Knows a Lot About That! has 40 half-hour episodes. PBS Kids renewed it for a second season of 20 episodes which premiered on September 10, 2012. A 20 episode third season is currently in development. Each episode features The Cat in the Hat (voiced by Martin Short), who leads neighbours Nick and Sally, the Fish, and Thing One and Thing Two on a variety of adventures in his "Thinga-ma-jigger", a Seussian contraption that can sprout wings, pontoons, booster rockets, change size, and do just about anything else necessary to further the adventure. The adventures are prompted by a question posed by either Nick or Sally
The Cat in the Hat (TV special) house they visit has a pessimistic fish who "always tries to flatten the fun". Karlos becomes angry and accuses the Cat of not being a real cat, and his hat of not being a real hat. But the Cat indignantly asserts his legitimacy by singing his name in several languages. The tune becomes so catchy that everyone, even Karlos, joins in and contributes, telling the Cat that in Russian he is a "chapka in a shlyapa". (An interesting point to note is that in the Russian portion of the song, the Cat describes himself as a "chapka in a shlyapa",