In a British suburban community, groundskeeper Crickle prepares for a school's re-opening after the holidays. One of its staff, Professor P. Popper, is a diminutive and bespectacled science teacher who is extremely eccentric. A wider group of Popper's student assistants—Terry, Angus, Carol, and Peter—mistakenly join the pair in their predicament after searching for them. However, Liz, another of the Professor's tutees, avoids the fate of her classmates and is consequently tasked with helping them in their plight. Initially confined to Popper's chaotic laboratory, the affected group are now two inches tall, each the size of an insect. Their environment is greatly altered as a result; a book is now like a cliff edge, the
rotary dial resembles a
carousel, pennies are the size of
hula hoops and a cat's paw is as large as a
Ford Transit. Popper's colleague, Professor Crabbit (dressed in the attire of
Sherlock Holmes), meanwhile sets about investigating what has happened to the cohort, arousing the suspicion of local man Rollins. Having misplaced the antidote to his formula, Popper's shrinking powder further becomes a prime target of theft. Covert Russian operatives bent on
industrial espionage and a
London gang, the latter sporting two crooks sent to miniaturise the
Bank of England and sell it to the United States in a suitcase, initiate their pursuits. The danger is eventually supplemented by the Professor's group being chased by an enlarged
tarantula, as well as a perilous
roller skate ride through the capital. Still, the formula is protected by Popper through this trepidation, and all the villains' plans are ultimately thwarted. Having finally discovered an antidote, normality resumes for the schoolchildren and their teacher. ==Cast==