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.
Unfortunately the movie What Waits Below is not yet available on HBO Max.
| Production | Sandy Howard | Producer |
| Directing | Don Sharp | Director |
| Production | Robert D. Bailey | Producer |
| Writing | Freddie Francis | Story |
| Sound | Michel Rubini | Original Music Composer |
| Production | Jim Garrard | Casting |
| Production | Victoria Plummer | Production Coordinator |
| Editing | John R. Bowey | Editor |
| Sound | Denny Jaeger | Original Music Composer |
| Production | Mel Pearl | Executive Producer |
| Art | Stephen Marsh | Art Direction |
| Production | Jeffrey M. Sneller | Associate Producer |
| Production | Don Levin | Executive Producer |
| Writing | Robert Vincent O'Neil | Screenplay |
| Costume & Make-Up | Pamela Hallisey Hiss | Makeup Artist |
| Crew | Doug Bledsoe | Stunts |
| Crew | Clarke Coleman | Stunts |
| Writing | Christy Marx | Screenplay |
| Sound | David Lee | Sound Mixer |
| Camera | Virgil L. Harper | Director of Photography |
| Sound | Craig Felburg | Sound Mixer |
| Crew | Bret Culpepper | Special Effects |
| Crew | Ron Bledsoe | Stunt Coordinator |
| Crew | Mike Bledsoe | Stunts |
