Earth has been taken over by a strange alien force - creatures whose instinct for survival overrides any human resistance. A vital weapon, capable of electronically warping the mind, falls into the hands of a terrorist group still strong enough to oppose the aliens. This weapon is so powerful that it cannot be controlled, placing the control of Earth in a terrifyingly precarious balance.

The Ganymede Takeover is noted for its exploration of alien invasion themes, drawing parallels to Philip K. Dick's earlier works. The narrative centers on the struggle for Earth's control against a formidable alien force, amplified by the introduction of a dangerous mind-warping weapon. The book's premise suggests a tense conflict where survival instincts clash with the potential for catastrophic technological misuse. Its origins as a potential sequel to 'The Man in the High Castle' also offer a unique perspective on Dick's thematic explorations.