A university graduate assistant, Greg Stevens,studying physics, learns that a giant meteor he has been tracking is going to cross the moons orbit. It actually hits the moon, slowing it and shattering it into small rocks and dust, which fall to Earth. During the twenty-eight day spiraling descent of the debris, Greg fills his pre-WWII fallout shelter with whatever he thinks might help him survive the confluence.He emerges months later to find a moutainous moonscape around him. A few miles away he finds an armory basment full of necessities, including food, fuel and vehicles. A young boy, Albert, joins him, and he meets a college-age girl, Lee, at an airport, where he had taken flying lessons.Greg and Lee rescue five children and romance blossoms, as they become a family. Using an airplane, he and Lee discover they are on an island, and they share their supplies with survivors that show up. They form a and choose Greg as their Captain.Julia is asked to be the religious leader and she influences them to accept polygamy, since there are twice as many women as men. She also gets them to vow, "Im going to enjoy the life Ive been privileged to keep and help others to enjoy life also."Carla, an attractive woman, Gregs age, joins Gregs family. Lee likes her; controlling occasional feelings of jealousy. They name the island Atlantis.Dr. Gwen Vries, an administrator in whats left of a univeristy north of the mountains, has convinced the surviving professors that she should be President, and she tries to extend her control to the area south of the mountains.Civil war erupts, and her followers defect. Greg prefers teaching to politics and sets up an oligarchy, ruled by the Atlantis Council, a group of people who have proved themselves to be honest and talented.After thirty years of industrial and economic growth and a burgeoning population, Atlantis establishes a colony, Plymouth, on the mainland.A tribe of vicious cannibals, armed with crossbows, attacks Plymouth. Gregs adopted children and Carla join the effort to handle the problem, while the Atlantis Council receives a disturbing radio message. A town, New DC, claims to be the capitol of the US, and John Claymore has been chosen to be The President.A radio dialog ensues, and New DC says its Air Force has annihilated the cannibal terrorists. The Atlantis Council is skeptical but follows the radio signal with three jet aircraft to salute New DC for their victory. While doing a wing waggle salute over the small towns single hangar airport, the Atlantis pilots notice the New DC air force consists of three antique Stearman biplane trainers.New DC sends the message that Claymore has resigned and New DC recognizes the Atlantis Council as the government of the US.Greg realizes Atlantis is no Shangri-La, but he is happy with Lee and Carla, and he is proud of the younger generation, who are taking over his new world. He is excited about his physics professorship at the new university and feels that life is just beginning.