Six rough and tumble motor cyclists meet at the side of an empty highway to plan their adventurous excursion cycling to Los Angeles. The burly bunch are Michael (John Alderman), David (Tom Basham), Henry (Bob Bihiller), Arnold (Bruce Kimbal), Eddie (Henry Olek) and Ronnie (Maurice Warfield). They're deceptive: although they look like the adventure addicted non-conformists of today out to raise Hell as they brawl their way over countryside and local towns, actually the six are on a different type of trip to the City of the Angels.

A team of men and women investigate the mysterious deaths of two previous expeditions to a strategically important but barren world.

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.