Eccentric and absent-minded inventor Wayne Szalinski and his amazing shrinking machine have returned in the final installment in the Honey, I Shrunk the Kids trilogy, as he decides to use it just one more time, before donating it to the Smithsonian Institution. Accidentally activated twice, the machine causes Wayne, his brother, and their wives to shrink! Soon, they must fight to get away from giant insects, a treacherous loop-the-loop track in a toy race car and other threats to the existence of the suddenly tiny.