A surgeon transplants the heart of an ape into his ailing son with horrific results.

The advertising director of Pacific Pharmaceuticals, frustrated with the low ratings of their sponsored TV program, seeks a more sensationalist approach. He orders his staff to Faro Island to capture King Kong for exploitation. As Godzilla re-emerges, a media frenzy generates with Pacific looking to capitalize off of the ultimate battle.

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!