Two scientists, Bensington and Redwood, conduct research into the growth process of living things. The result is a chemical foodstuff (which they name Herakleophorbia IV) that accelerates and extends the process past its normal cycle. Setting up an experimental farm, the pair test the substance on chicks, causing them to grow into giants.
Unfortunately, the slovenly couple hired to feed and monitor the chicks allow other creatures to eat the food, and soon giant rats, wasps and worms are terrorizing the countryside. The chickens then escape and overrun a nearby town. Urged on by a civil engineer named Cossar, Bensington and Redwood take responsibility for the mayhem. Armed with buffalo rifles and explosives, the men hunt down the monstrous vermin and burn the experimental farm to the ground.