British B-movie shot at Merton Park Studios which presents a new take on the King Kong story. Madcap botanist Dr. Charles Decker (Michael Gough) believes he has discovered a serum which helps plants grow to an abnormal size. Deciding he'd like to test it on animals, he introduces the serum to a chimpanzee called Konga and watches it grow to the size of a gorilla. Drunk with power, the scientist takes Konga to London to wreak revenge on his enemies. However, when his girlfriend Margaret (Margo Johns) discovers that Decker also plans to use Konga to help him steal the heart of his unrequited love Sandra (Claire Gordon), she gives the ape an unhealthily large dose of the growth treatment. Now the size of some of London's most famous landmarks, Konga wreaks havoc in the British capital as he searches for the man who has deformed him.