Dr. Rhodes explains that he has discovered that a nuclear-explosion-driven mining machine that he invented for Terraluna will actually blast the moon apart, sending debris raining down onto Earth and destroying civilization.

The ship is launched up the side of a mountain, much of the initial boost being provided by a series of magnetic rings (similar to the ringroad that Robert Heinlein described in Starman Jones).

While waiting for radio contact to resume, Bruce and the others find artefacts, signs that an alien city once occupied the ground on which they stand and has since crumbled into the gravel on which their ship and camp sit.

With some effort and luck he finds his father, whose rocketboat had broken down, and the two men return to Mimas just in time to see Garcia and Benz take off in their rocketship and head for Hidalgo.

The book was reviewed by “Another father and son team of scientific superiority, sally to Saturn – to prove their innocence and even an old score with a greedy gang who want to blow up the moon for the minerals therein.