The story begins in 1944 and covers more than 30 years in the lives of four men and their families: Dieter Kolff, a German rocket engineer who worked for the Nazis; Norman Grant, a World War II hero turned U.S.

Senator from the fictional Midwestern state of Fremont; Stanley Mott, an aeronautical engineer charged with a top-secret U.S. government mission to rescue Kolff from Peenemünde; and John Pope, a small-town boy turned Naval Aviator who becomes a test pilot and then an astronaut.

An exceptional and unexpected burst of sunspot activity results in the death of Claggett and Linley: the two astronauts are exposed to a lethal level of radiation while out on the lunar surface during a large solar flare.

On the human side, various subplots run through the novel, contrasting the "official" heroism of NASA with the human fallibilities of the cast—the difficulties the Kolffs face in integrating into American society; Norman Grant's initial embrace of the space program and his abandonment of it as it no longer serves his political aims, while his unstable wife and their daughter fall in with a highly intelligent but cynical cult leader calling himself Leopold Strabismus, who exploits first the UFO craze and then an anti-scientific creationist agenda to increase his wealth; Randy Claggett's womanizing; the contrast between Stanley and Rachel Mott's ordered, rational existence and their troubled relationship with their sons, and John Pope's unusual yet supportive relationship with his lawyer wife Penny.

Pope retires from NASA and becomes a respected professor of astronomy, his wife Penny is elected to the Senate, and Mott is consulted on "Grand Tour" uncrewed missions to the outer Solar System, as well as the development of the Space Shuttle.