To prove that the massive symbionts, named Leviathans, that inhabit Jupiter's atmosphere possess intelligence, physicist Grant Archer readies a deep-pressure manned probe for immersion in the giant planet's deadly cloud cover. Equally anxious to thwart his attempt, millionaire Katherine Westfall seeks to outmaneuver Archer in her bid for the top spot in the International Astronautical Authority (IAA) by any means possible--including murder.