In a tributary of the Amazon, a monster – half-man, half-fish – is captured and placed in a reservoir in a Florida national park to be observed by scientists.
John Agar
Prof. Clete Ferguson
Lori Nelson
Helen Dobson
John Bromfield
Joe Hayes
Nestor Paiva
Captain Lucas
Grandon Rhodes
Jackson Foster
Dave Willock
Lou Gibson
Robert B. Williams
George Johnson
Charles Cane
Police Captain
