Dr. Decker returns from Africa after a year, presumed dead. In that year, he discovered a way of growing plants and animals to an enormous size. He brings back a baby chimpanzee to test out his theory. As he has many enemies at home, he decides to use his chimp, 'Konga', to 'get rid of them'. Then Konga grows to gigantic proportions and wreaks havoc all over London!

A small time thief is recruited by a mobster to help with the racketeering. He doesn't like the job, but with the mob on his back, a femme fatale in his bed and a sick friend to care for, he will have to keep all his wits about him.