The US military is running a test for a special type of radio transmitter, to be used to communicate with submarines, in a deep system of underground caves in Central America. When the signal from one of the transmitters suddenly disappears, a team of soldiers led by Major Elbert Stevens and cave specialists led by Rupert 'Wolf' Wolfsen including scientist Leslie Peterson are sent in to find out what happened. Exploring deep underground, they stumble upon a tribe of albino cave-dwellers who have apparently been isolated from the rest of the world for thousands of years. The cave-dwellers are hurt by radio frequencies and are able to see in infra-red frequencies, tracking the explorers by their body heat.
| Production | Robert D. Bailey | Producer |
| Directing | Don Sharp | Director |
| Production | Sandy Howard | Producer |
| Production | Don Levin | Executive Producer |
| Writing | Freddie Francis | Story |
| Production | Mel Pearl | Executive Producer |
| Production | Victoria Plummer | Production Coordinator |
| Sound | Denny Jaeger | Original Music Composer |
| Editing | John R. Bowey | Editor |
| Sound | Michel Rubini | Original Music Composer |
| Production | Jim Garrard | Casting |
| Art | Stephen Marsh | Art Direction |
| Production | Jeffrey M. Sneller | Associate Producer |
| Camera | Virgil L. Harper | Director of Photography |
| Writing | Christy Marx | Screenplay |
| Writing | Robert Vincent O'Neil | Screenplay |
| Costume & Make-Up | Pamela Hallisey Hiss | Makeup Artist |
| Sound | Craig Felburg | Sound Mixer |
| Sound | David Lee | Sound Mixer |
| Crew | Bret Culpepper | Special Effects |
| Crew | Doug Bledsoe | Stunts |
| Crew | Mike Bledsoe | Stunts |
| Crew | Ron Bledsoe | Stunt Coordinator |
| Crew | Clarke Coleman | Stunts |
