Rear Admiral Gale Harkness's ship, the Argos, under the command of Captain Bernice O'Reilly is despatched on a mission to discover the fate of two remote outposts of humanity that have gone silent. To discover that both colonies have been totally obliterated, with the exception of one young girl, is a shock in itself, but when Gale and her crew are assaulted by hurricanes, earthquakes, and volcanoes that seem to have no basis in nature, she has to ask whether an alien intelligence is involved. The sudden appearance of a myth used by the Shi-az-ee to frighten their children, causes an almost fatal shock to humanity's newest ally, leaving the humans as the only possible defence against a race that seems to be intent on exterminating all other intelligent lifeforms.