The Earth was weakened by the losses of World War III. Not long after, the worm-like telepathic beings inhabiting Ganymede appeared and easily took over the planet, but they soon discovered that maintaining their power was not as easy as they thought.

It was not possible to completely eliminate the resistance of the earthlings, and people are causing countless, unforeseen problems. For example, a group of guerrillas finds weapons hidden in World War III, which were not used because of their terrifying power, but no one has any moral concerns about foreign invaders.

The Ganymedesians are determined for the final solution, but they do not count on such individuals as guerrilla leader Percy X, dr. Balkan psychiatrist and television personality Joan Hiashi.

The joint novel by Philip K. Dick and his childhood friend Ray Nelson is an alien invasion story, but at the same time a plastic and still relevant examination of the relationship between power and the individual.