In this 9th book in the Tom Swift Invention Series, Tom must suffer disappointment when a contract to build habitats for a Moon colony go to another, inferior, bidder. The result is a catastrophe, and Tom must mount a mission to recover the bodies of nearly a third of the colonists. When Swift Enterprises offers to build a protection system, that offer is rebuffed for no good reason. Angry, Tom decides to set his sights on an even more ambitious project: a colony on Mars! It will need to be huge and totally self-sustaining as no "quick resupply" system will be available. With a good understanding of the weak points of the lunar buildings he begins developing an inflatable habitat. He sneaks up to the Moon for a test and runs afoul of the company that built the fragile structures. He is even attacked by their rocket. Or, is it them? There are rumblings that Tom's old enemies, the Brungarians, are up to their old tricks and might be trying to sabotage Tom's efforts. Whoever it is, they seemed determined to stop Tom Swift!