British librarian Ken Harper must face being torn suddenly from his great love Betty Gibson after they finally acknowledge and consummate a years-long love. Ken awakens on a beautiful world with two moons which is occupied by another woman, crass American bicycle tour guide Nancy Perry. This world of great mystery holds the answer to man's survival of human extinction under the impending celestial hammer of a huge asteroid.
Ken tries for months to find a way back to Earth and his Betty, while Nancy wants nothing more than to have him for herself. Ken's love for Betty is strong and so is his resolve to resist the wiles of an increasingly alluring Nancy-a Nancy who is changing to a new form of human-a change orchestrated by an ancient Artificial Intelligence who has a plan of rescue for the human race.
This ancient AI, Saldana, has contacted Jim and Angela Manning, the two people closest to Nancy Perry's departure point, as they, like Ken and Nancy, have been infused with advanced nanotechnology to fulfill the terrestrial side of Saldana's human survival plan. They must gather 300 of earth's best and brightest while their genius children infiltrate NASA's ranks to build Exodus Ships in secret to bring them to Mars, Despite selection safeguards, an insane recruit is bent on the destruction of the Exodus members for leaving behind the people of Earth.
Saldana can see across the threads of possibility she sets in motion by her interference with the natural course of human events, and many false starts range from man becoming extinct form interplanetary nuclear exchange or die-out from simple apathy. Saldana discovers a key individual whose invention frees man from the confines of the Solar System, but there are many parallel histories in which her plan fails. Will she discover the right timeline to ensure long-term survival?
