Astronomers discover a comet that they believe will crash into Phoenix, Arizona. They attempt to warn officials, but without 100% certainty, the governor of Arizona is reticent to cause a panic. Even after a television news reporter discovers the truth and threatens to go live with it, the response is understated enough to doom some residents of Phoenix to certain death.

During World War II the passenger liner "Goliath" is sunk by a German submarine. Portions of the ship's hull remain airtight, and some of the passengers and crew survive. Over the decades they build a rigidly regulated society completely isolated from the surface world until, in contemporary times, a diving team begins to explore the wreck.