The shortest kid in the second grade, James Moody, also known as Stink, learns all about the shortest president of the United States, James Madison, when they celebrate Presidents' Day at school.
A mother provides examples of how her toddler is both big and little, including little enough to ride through the park in a stroller but big enough to make the pigeons fly away.
Andrew, his cousin Judy, and Thudd the robot, having been shrunk by a shrinking machine, encounter many terrifying creatures, including Mrs. Scuttle, as they try to reach the Atom Sucker before it explodes.
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.
When ten-year-old Andrew invents a shrinking machine, he does not expect to be sucked into the machine along with his cousin Judy, only to end up in a dog's nose.
After being shrunk by a shrinking machine and ending up on a dog having a bubble bath, Alexander, his cousin Judy, and a tiny robot try to survive encounters with insects, soapy bubbles, and bathtub and toilet drains.
Andrew, his cousin Judy, and Thudd the robot wind up at a garbage dump when Andrew's latest invention, the Goa Constrictor, shrinks them to the size of beetles and swallows them.