In this hardbound second installment of the Lunar Trilogy (Tom Swift and the Space Battering Ram was part 1) an environmental disaster hits California at the same time the lunar colony-now free of the tyranny of the Masters-is facing a crisis of their own, and it seems a single solution needs to be found for both. At the same time, Harlan Ames ventures to Tibet in search of answers about the Empress and where she might have crashed her evacuation spacecraft. What he finds will turn his world on end and nearly ruin the now-free colony on the Moon. With his own troubles, Tom must find a way to mine water from a passing comet and bring it to the Moon and down to the Earth safely and quickly before people start to die. As it is, people are leaving the state as if it is becoming a new dustbowl. The inhabitants of the lunar colony don't have that luxury. Will Harlan's search and Tom's projects succeed? Or, with they intersect with disastrous consequences?