Jaybee Corbell, a 2190 starship pilot reconstituted from a 1970s cancer victim in cryo-storage, returns from an interstellar joy ride to a 3,000,000 A.D. solar system full of misplaced parts, with Earth orbiting around an unaccountably hotter Jupiter. From a lone, crazed woman survivor of an earlier age, the now elderly Corbell learns that an ancient secret of immortality survives somewhere on the planet; from the currently governing race of ""Boys"" he learns that the long-lost planet Uranus is even now being hurled on a collision course toward Earth. Niven, best known for Ringworm (1972), fiddles madly with the surreal-chase elements of his plot; the entire result is disjointed and over-intricate but terrific fun.