When kids sneak into inventor Wayne Szalinski's (Rick Moranis) upstairs lab to retrieve an errant baseball, his experimental shrink ray miniaturizes them. When Szalinski returns home, he destroys the device -- which he thinks is a failure -- and dumps it in the trash, throwing out the kids along with it. The four children, now 1/4-inch tall, must survive the journey back to the house through a yard where sprinklers bring treacherous storms and garden-variety ants stampede like elephants.