A subterranean monster, the Earth Eater, is destroying San Francisco from below. It gobbles up earth, parts of buildings, and other vital parts of the city. The researchers aboard the Calico fall underground through a hole created by the Earth Eater. Rather than scrambling back out to the surface, the enterprising group decides to investigate. Soon thereafter, the Earth Eater traps and menaces them. The adventurers call upon Godzilla to rescue them.
—Ken Miller <wkmiller704@yahoo.com>