The King of Mars commands the dreaded Lobster Man and his assistant Mombo, a gorilla wearing a space helmet, to pilot his flying saucer to Earth then steal its air.

On a lonely road, John and Mary, a young and innocent couple discovers the hiding place of the flying saucer in a dark and mysterious cave.

Successfully contacting Professor Plocostomos, a plan is created to lure the Lobster Man to Mr. Throckmorton's Haunted House that just happens to be surrounded by boiling hot springs.

A wild chase ensues, but Professor Plocostomos uses the hot engine coolant from his overheated vehicle to drench Mombo causing his foamy demise.

The chase concludes in Yellowstone National Park where the dreaded Lobster Man is tricked into walking into the Old Faithful Geyser and a steamy demise.