When Uncle Al is kidnapped by Dr. Kron-Tox and sent to prehistoric times, Andrew, his cousin Judy, and Thudd the robot try to use Uncle Al's latest invention, the Time-A-Tron, to rescue him, and learn first-hand about the origins of the universe.
Andrew, Judy, and Thudd travel in the newly repaired Time-A-Tron to the Ice Age in an effort to rescue Uncle Al, who is stranded somewhere on the frozen tundra, and make it back to the present in time to thwart the evil plans of Doctor Kron-Tox.
While bouncing through Earth's prehistory in a malfunctioning time machine, Andrew, his cousin Judy, and Thudd the robot meet Dr. Kron-Tox's nephew, Beeper, and nearly lose the Time-a-Tron in a tsunami.
Ten-year-old inventor Andrew Dubble takes his robot Thudd and his cousin Judy on a deep-ocean journey in the Water Bug, but they find themselves in a dangerous situation when the vehicle loses power while passing over the deepest place on Earth.
While trying to recover from their accidental underwater adventure, Andrew, his cousin Judy, and Thudd the robot are swallowed by a blue whale, the world's largest creature.
Still reduced to the size of insects, Andrew, Judy, and the robot, Thudd, go to a pond, where they encounter dragonflies, moss animals, and fierce larvae in an attempt to learn why frogs are disappearing throughout the world.
Ten-year-old inventor Andrew Dubble, stranded in the past along with his robot Thudd and cousin Judy, must somehow dodge dinosaurs long enough to fix his time machine, and try to rescue Uncle Al who was dropped off in the Ice Age.
Andrew, Judy, and Thudd, shrunk down to the size of bugs by Andrew's Goa Constrictor garbage disposal machine, find themselves in big trouble when they are picked up by a bat and flown to a cave where bugs are regarded as a tasty treat.
When an electric fish shrinks Andrew, Judy, and Thudd to the size of bacteria, they end up being injected by a mosquito into Uncle Al's bloodstream where they must battle germs, parasites, and white blood cells.
Andrew, Judy, and Thudd, still the size of bugs, try to help a stranded Arctic tern and end up in the Australian rain forest which poses all kinds of problems for the minuscule trio.
